Loss of bone strength is one of the least talked about risks of sedentary lifestyles, but is arguably one of the most important, with osteoporosis related fractures occurring in one in three women and one in five men. There is a direct relationship between the lack of oestrogen after menopause and the development of osteoporosis.

As a society, we are more sedentary than ever before. The use of transport, electric rather than manual bikes, and having our weekly grocery shopping ordered online and delivered to the comfort of our homes are all at odds with keeping active. Children in particular are less active – with computer games replacing “playing out” during a crucial time of development when exercise (especially jumping) can optimise bone strength gains by up to 5.5% over six months.

Research is also demonstrating that what’s known as “epigenetic memories” may also be passed down several generations, which means that our lifestyle today could influence gene expression in future generations. If sedentary trends continue, humans are at risk of becoming frailer and more dependent – needing increased support from already stretched health services.

The science

Our skeleton has many roles: it supports our body, provides attachment points for muscles, tendons and ligaments that enable our bodies to move, and stores minerals like calcium and phosphorus. However, when external forces and demands are removed, our muscles can waste, and our bones become lighter, less dense and less “useful” – this increases the risk of osteoporosis and fracture.

A loss of around 3% of cortical bone in the leg, for example, can occur during one month of bed rest, and in space, astronauts can lose over 10% of their bone strength on a typical 120-180 day mission. This is because of the absence of loading to the skeleton in the microgravity environment.

Our current ongoing research shows that sedentary time is a risk factor for reduced bone strength in middle age. Reduced activity after retirement and sitting for prolonged periods of time, are shown to be the main factors as this removes functional stimuli to bone – as does letting robotics and machines take over tasks we used to do for ourselves.

On the other hand, when bone is “loaded” through various forces, it responds by becoming stronger. This is evidenced by numerous exercise intervention studies, and previous research shows around 20-30% greater bone strength in athletes from “impact” sports – such as football, hockey and running – compared to non-athletes.

Lessons through time

Analysis of bones from over hundreds and thousands of years ago suggests that our skeleton today is more fragile than that of our ancestors, and the differences became more pronounced when humans started to farm their food (domesticating animals and plants).

Before this time, humans foraged wild plants and hunted animals. They were much more active than their descendant farmers, ate leaner meat, and were more often than not, “on the move”. Research has found that their bone mass was around 20% greater. A decrease in leg bone size and changes in its cross-sectional shape are also evident at the advent of farming. This reflects changes in loading on the skeleton due to the different activities people did.

Research also suggests that prehistoric women in the Neolithic, Bronze and Iron Ages had around 5-10% more arm bone strength than modern female athletes, indicating heavy use of their arms for specific activities. This suggests modern humans are falling short of their bone strength potential.

What you can do

Simple exercises and lifestyle changes that are similar to activities of a hunter gatherer can help build bone strength. Interval training and sports including bouts of fast sprinting such as football, along with lifting weights can help. But it doesn’t have to be all about going to the gym, simple changes like using a rucksack when walking and shopping can increase loading to the spine.

Do your own food shopping as often as you can, and carry your own shopping bags to provide some loading to the arms and back muscles – and also indirectly to your legs (and all related bones).

Walk more often and further and with your dog if you have one. Park your car further away from work or the shopping centre, take regular walking breaks at work and at home and hold walking meetings or practice social walking with family and friends. Aim to use the stairs instead of escalators or a lift and try to take two stairs at a time to get a glute and quad work out while loading the bones at the hip joint.

Regular gardening and having a vegetable plot or even an allotment can offer similar advantages, as can doing housework vigorously. And if you have a wood burning stove, chopping your own logs goes some way towards mimicking how our ancestors prepared their kill and building materials for shelter.

These small changes can help to build bone strength – which is vitally important given that the number of people aged 50 years and over with a high risk of osteoporotic fracture was 158m in 2010 and is projected to double by 2040 globally. And while increasing life expectancy may be part of the explanation, lifestyle habits unfavourable to bone health and strength are also a large part of the problem.

• Karen Hind is an assistant Professor in Sport and Exercise Sciences, Durham University. Charlotte Roberts is a Professor of Archaeology specialising in bioarchaeology (human remains), Durham University.
• This article first appeared at The Conversation. It is reproduced here with permission.
• For more on how to protect your bones see our article How to prevent brittle bones.

Your body needs salt to function normally, but an excess leads to raised blood pressure and an increase in the risk of stroke and heart disease. Since prevention is better than cure, the government has ambitious plans to get the public to consume less salt.

The recommendation for salt intake is to limit it to only 6g a day (about a heaped teaspoon). However, the average intake is closer to 8g a day. The statistics suggest that if the 6g a day target is achieved, it will prevent over 8,000 premature deaths each year and save the NHS over £570m, annually.

But food without salt is bland, and low-salt products are often bland compared with their standard counterparts. Salt in food gives us that highly desirable lip-licking taste on the tongue that makes food interesting and enjoyable. It also boosts the flavour of food, which is what we experience when we combine the tastes from the tongue with the aromas we detect with our nose.

So, can we reduce the salt in our diet yet keep all the delicious flavours we crave? This is a problem the food industry has been working on for years.

Over the last 15 years, a concerted effort by industry and public health campaigns has seen the nation’s average salt intake decrease by 10%. Part of this decrease is down to the fact that we are slowly becoming more accustomed to food with less salt, and part of it is down to the fact that scientists now understand more about the perception of saltiness.

Tricks of the trade

One approach the food industry has taken is to change the size and shape of the salt particles so that more of them reach the receptors on the taste buds on the tongue. This addresses the lack of salty taste when the amount of salt in processed food is reduced. But a different approach is needed to address the lack of overall flavour.

At home, this can be overcome by adding more herbs and spices. Another trick is to add foods that contain natural flavour enhancers, such as tomatoes or parmesan cheese, and combine these with low-salt soy sauce or tiny amounts of fish-based sauces, such as Worcester sauce, which contains anchovies. This works well because the nucleotides found in the fish and in the soy sauce work together with glutamic acid found in tomatoes or in cheese to give a more powerful savoury flavour.

We can further enhance the perception of saltiness by adding low levels of aromas that we associate with salty foods. This is the savoury version of adding vanilla to low-sugar products to give the impression that they are sweeter.

Researchers have tested complex flavourings as well as single aroma compounds for their ability to make us believe there is more salt in food than there actually is. The aromas that have been tested smell like meat, sardines, cheese or anchovy. And because we associate these foods with saltiness, we perceive the product as saltier, even though no salt has been added. In other words, we can trick the brain into thinking we are tasting salt.

There is also a backup plan. Researchers at the University of Reading have shown that the more we consume no-salt soup, the better it tastes. The participants in this study did not particularly like the no-salt soup, but after consuming it once a day for a week, participants liked the taste more than when they first tasted it. So you can always train your brain to enjoy a low-salt diet. It just takes practice.

• Jane Parker is an Associate Professor, University of Reading.
• This article first appeared at The Conversation and is reproduced here with permission.
• For a comprehensive look at the pros and cons of salt cponsumption see our article  Tackling the ‘salt is bad for you’ myth

Recently, researchers have been learning more about how poor sleep influences our dietary choices, as well as how diet influences sleep quality. Not sleeping for long enough or poor quality sleep are associated with increased food intake, a less healthy diet and weight gain. Lack of sleep also leads to increased snacking and overeating. And it causes us to want to eat foods high in fat and carbohydrates – with increased chemical rewards to the brain when we do eat these foods.

Essentially, poor sleep drives your body to find high energy foods to keep you awake which makes fighting the cravings for unhealthy foods very difficult to resist. But, on the other hand, when we have slept well our appetite hormones are at a normal level. We don’t crave unhealthy food so much – and we can make better choices about what to eat.

The science of sleep

All cultures around the world have traditions about which foods promote sleep. Foods such as milk, chamomile, kiwi fruit and tart cherries, have all been said to work wonders for a good night’s sleep. Given how much the food we eat affects us on a day-to-day basis, it is not surprising that our diet plays such a big role in our quality of sleep. What we eat also has a big impact on our organ function, immune system, hormone production and brain function.

A really important hormone that controls our sleep patterns is melatonin. Melatonin is produced in the brain and the amount of melatonin you produce and how efficiently our brain uses it is affected by our diet. One of the biggest influence on our melatonin levels appears to be our intake of a type of protein called tryptophan. Tryptophan is an essential amino acid – the building blocks of proteins. Essential amino acids are a group which our bodies cannot make, it can only be sourced through diet.

Other nutrients that appear to be helpful for sleep include B vitamins and magnesium. This is because they help tryptophan to be more available in the body. If your diet is lacking tryptophan, B vitamins or magnesium. It is very likely that your melatonin production and secretion will be affected and your sleep quality will be poorer.

Eat to sleep

It stands to reason then that following overly restrictive diets or diets that put you at risk of nutrient deficiencies can really affect your sleep. But by increasing your intakes of foods rich in specific nutrients, it may well help to promote better sleep quality and duration.

Dairy foods, for example, can be great at helping you sleep. Not only is dairy an excellent source of tryptophan, but it also contains magnesium and B vitamins which help to promote the activity and availability of tryptophan. Nuts, like dairy, also contain all the nutrients known to promote increase melatonin production and support its release.

Fish is a great source of tryptophan and B vitamins. Fish with bones, such as sardines, will also provide magnesium. Including fish in your diet regularly may help to promote healthy melatonin production when you need it. Pulses, beans and lentils also contain high amounts of tryptophan and B vitamins. Adding some tofu or paneer to a vegetable stew or curry can also help to increase your likelihood of having a great night’s sleep. You could also add in some soya – which is another good source of tryptophan – to optimise your sleep potential.

And if you’re still struggling to sleep, it might be that you’d benefit from some meat. Meat of all kinds contains all the essential ingredients for a good night’s sleep. So if you can’t nod off at night, maybe think about adding some lean meat to your diet.

If you find yourself hungry before bed, for the ideal bed time snack, try a glass of semi-skimmed or skimmed milk, a small banana or a few nuts – all of which can really help to improve your sleep and your willpower the next day. It’s also worth pointing out that it takes around an hour for the tryptophan in foods to reach the brain, so don’t wait until just before bedtime to have your snack. And it’s also advisable to have a balanced diet that includes plenty of foods that are high in tryptophan throughout the day to optimise your chances of a good night’s sleep.

• Sophie Medlin is a ‎Lecturer in Nutrition and Dietetics, King’s College London
• This article first appeared on The Conversation. It is reprinted here with permission.
• For more on getting a good night’s sleep see our article  How to get a good night’s sleep. You can also follow this link for a selection of stories on the importance of sleep.

Many of us wish for lives that are free from stress but, in fact, we do need stress in our lives, though stress can be either positive or negative.

Positive stress is the stress that gets us up in the mornings. We need this type of stress, or adrenaline to get us going, spur us on to do things and achieve our goals.

Negative stress places extra burdens on us, we begin to feel anxious, tired, drained. It’s when it turns into negative stress, that’s when the problems begin. Over the long term it can have detrimental effects on our bodies and minds.

So, with this in mind, how can we even start to think of reducing this negative stress?

Firstly, ask yourself, what the factors in your life are that are possibly causing the stress. Often it’s things like a demanding job, family or health issues and sometimes reducing these kinds of stresses is easier said than done. You cannot just remove these factors from your life.

But when it comes to how you behave within certain situations it can come as a surprise to learn that you can indeed change how you perceive these factors. Small changes can mean big improvements on your perception and then consequently have a positive outcome for you.

Getting started

When looking at ways to reduce negative stress, there are several methods to choose from.

• First exercise. Yes, you can do this! It doesn’t have to be full on interval training either. Gentle yoga or Pilates, a refreshing walk in the park or stretches can influence the production of endorphins or feel good hormones to be released into the body. This allows you to feel and become more settled and promotes calmness, something we all need more of these days.

• Then try meditation. We are always on the go, living in society which seems to promote a busy lifestyle as being the only way to live. Not so, in my opinion. Meditation is one way to deal better with this modern way of life. Of course it is easy to think you couldn’t manage to do this, as it appears on first glance that you have to try and erase thoughts from your mind. This is a common misconception about meditation. Instead the purpose of mediation is to try to promote a slower, calmer, more peaceful state of mind. Taking 10 minutes of your day out to do this, effectively stops the mad rush of life for a few moments. This act in itself has positive effects on the mind and body.

A complementary path

As a complementary health therapist I often deal with clients who suffer from negative stress issues. In addition to the suggestions above, there are complementary approaches you can use in order to try to relieve the effects this negative stress has on you at any time.

One such method is the renowned Bach Flower Remedies. There are 37 in total, and were first established by Dr Edward Bach. It is said that these potentised plant essences have the potential to mediate emotional states, from that Monday morning feeling to more extremes of jealousy, guilt, various anxiety states.

If you keep a diary for a week or so, writing down how you feel at certain times of the day, you may get a pattern of your most commonly occurring emotional states. This will help you choose your particular remedy to suit you. Once you have your remedy keep it handy and try just a few drops under the tongue when you feel these emotions arise, or dilute a few drops into a glass of water and sip throughout the day.

Some Bach Flower Remedies which comes to mind are larch, for confidence issues, hornbeam, for that having the early morning blues feeling, holly, for jealousy and coveting others lifestyles, white chestnut, for those who lie awake during the night with niggling worries.

The beauty of using these remedies is there are no known side effects. If you are still in doubt as to buying your own, you can always seek advice from a qualified Bach Flower Remedy practitioner.

Using aromatherapy can be of great benefit, too. Of course receiving massage can be very helpful in relaxing the mind and body in harmony. However you can also use essential oils to create scent which will penetrate through the nasal passages into the part of the brain which controls the emotions.

Essential oils which are commonly used for stress are lavender, chamomile and bergamot. Bergamot, in particular, is said to be a great uplifting oil, perfect for those experiencing mild depression, anxieties and general low mood. Combining these essential oils in an aromatherapy burner can provide a calming atmosphere around you, as well as scenting your environment with the most delicious of scents. Try these stress busting blends:

• For an uplifting blend, use 4 drops of bergamot, 3 drops of tangerine and 5 drops of lavender in an aromatherapy burner, mix with 10mls of water.

• Another burner blend combines 5 drops of chamomile, 4 drops of basil and 5 drops of lemon, again in 10mls of water. This provides a clean, fresh happy scent, basil is also great for the concentration too, which can sometimes be compromised when you are suffering from anxiety states. Just add your tea light and there you are, instant relaxation and stress management for the soul.

• Angela Mitchell is an aromatherapist. Her website is topnotetherapies.co.uk.
• For more on this topic search our site and/or see our article De-stress, naturally

Earlier research has also found that writing about negative emotions – getting things “off your chest” – can improve your mental health. And it seems to benefit physical health, too.

Stress affects your physical health, so it is thought that improvements in mental well-being might stop people becoming physically unwell. Research has shown that writing about negative emotions can lead to fewer visits to the doctor, fewer self-reported symptoms of ill health, and less time off work due to ill health.

Not many studies have investigated writing about positive emotions, but if writing about negative emotions helps people deal with their negative thoughts and feelings, then it’s possible that focusing on positive emotions might have a positive effect on people’s mental health.

Earlier research has shown that writing about positive experiences for 20 minutes a day, for three consecutive days, improved people’s mood and led to fewer visits to the doctor. Even writing for as little as two minutes a day about a positive experience has been shown to reduce the number of health complaints that people report.

While earlier studies showed that writing about positive experiences can improve your mood, we didn’t know what effect it might have on stress and anxiety.

Twenty minutes a day

For our study, we investigated whether writing about a positive experience – which could include anything from being moved by a good book, painting or piece of music, to falling in love – could reduce stress, anxiety and common health complaints, such as a headache, back pain or coughs and colds. We also wanted to know if it would be helpful for all people, regardless of their level of distress.

We recruited 71 healthy participants, aged 19 to 77, and randomly allocated them to one of two groups. We asked one group (37 participants) to write about the most wonderful experiences of their life for 20 minutes a day, for three consecutive days, and we asked the other group (34 participants) to write about a neutral topic, such as their plans for the rest of the day, over the same time frame.

We measured levels of anxiety, as reported by the participants, immediately before and after they completed their writing task. We found a significantly greater decrease in anxiety for those people who wrote about positive experiences, compared with those who wrote about neutral topics.

The participants also reported their levels of stress, anxiety and physical health complaints four weeks after they completed the writing tasks. Stress and anxiety decreased to a significantly greater extent for those who wrote about positive experiences after four weeks, compared with the levels reported before they completed the writing tasks. However, writing didn’t improve participants’ physical health problems.

We also found that writing about happy moments was effective, regardless of the levels of distress that people reported at the start of the study.

Because we excluded people with a diagnosed psychological condition, we can’t be sure that this technique would work in a clinical setting. It’s also important to note that in order for them to engage with the task, it wasn’t possible to blind participants to the treatment. Another limitation of our study was that we relied on self-report questionnaires, rather than using objective measures of mental and physical health.

Of course, emotional writing may not be for everyone. Personality traits, problems expressing emotions or a disinterest in writing might mean that for some people there are better ways to tackle negative emotions.

An advantage of writing about positive emotions to tackle stress and anxiety is its simplicity. Unlike many other strategies for improving psychological well-being, this task needs no training or time spent with a therapist. People can do it at a time and place that is convenient for them – and it’s free.

• Michael Smith is an Associate Professor of Psychology, Northumbria University, Newcastle
• This article first appeared in the Conversation. It is reproduced here with permission and  a short summary for ease of reading.

New research has found that a daily dose counters the worst effects of autoimmune diseases like rheumatoid arthritis, and it can also reverse kidney disease, heart disease and osteoporosis.

Baking soda, also known as bicarbonate of soda, is a raising agent commonly used in baking, but it also has enormous therapeutic value. It reduces acid levels in the blood – which can helps ease some of the symptoms of heart disease and osteoporosis – but it also moderates the immune system’s inflammatory responses. That means that auto-immune problems like rheumatoid arthritis—where the body is essentially attacking itself—can be eased.

And the improvements can be seen quickly, according to researchers from Augusta University in Georgia.

Bicarbonate of soda is already being used as a therapy to slow kidney disease, and this got the researchers wondering how it was doing this. Their work suggests that sipping a little baking soda in water every day moderates the response of the immune system from going into over-drive and producing an over-the-top inflammatory response.

In tests on laboratory mice and humans, they found that the soda had a double-effect of triggering the stomach to produce more acid to help digestion and also communicating with mesothelial cells that sit on the spleen’s surface.

Fast action

Mesothelial cells line body cavities, like the one that contains our digestive tract, and they also cover the exterior of our organs to quite literally keep them from rubbing together. About a decade ago, it was found that these cells also provide another level of protection. They have little fingers, called microvilli that sense the environment, and warn the organs they cover that there is an invader and an immune response is needed.

After a daily dose of baking soda – for the humans this was 2g (approx. ½ tspn) dissolved in 250 ml of water – for just two weeks, macrophages, the spleen’s immune cells, shifted from being inflammatory to anti-inflammatory.

“The shift from inflammatory to an anti-inflammatory profile was happening everywhere. We saw it in the kidneys, we saw it in the spleen, and now we see it in the peripheral blood,” said lead researcher Paul O’Connor.

Drinking baking soda, the scientists think, tells the spleen – which is part of the immune system, acts like a big blood filter and is where some white blood cells, like macrophages, are stored – to go easy on the immune response. “Certainly drinking bicarbonate affects the spleen and we think it’s through the mesothelial cells,” O’Connor says.

A hopeful remedy

According to O’Connor this is some of the first evidence of how the cheap, over-the-counter antacid can encourage our spleen to promote instead an anti-inflammatory environment that could be therapeutic in the face of inflammatory disease, Medical College of Georgia scientists report in the Journal of Immunology.

O’Connor hopes drinking baking soda can one day produce similar results for people with autoimmune disease.

“He notes that “It’s potentially a really safe way to treat inflammatory disease.” And hopes that hopes drinking baking soda can one day be considered a cheap and effective remedy for people with autoimmune disease.

• For more information on lowering acidity see our article Q&A: Acid versus alkali foods. For more on inflammation see Q&A: How do I know if I have chronic inflammation?

Cobalt is a naturally occurring trace element which has been used since ancient times for its blue colour in glass and ceramics. It is an essential dietary mineral in mammals at a low level and its presence is a result eating food stuffs containing trace elements of cobalt. It is also present in vitamin B12.

As a mined mineral it is a crucial component of the batteries powering an arguably indispensable daily gadget: the smartphone.

But when it comes to its dietary form, “The human health-supporting properties of dietary cobalt are underappreciated,” ​argued the paper’s authors, Dr Michael Glade, a Hawaii-based clinical nutritionist, and Dr Michael Meguid, professor emeritus of surgery, neuroscience and nutrition at the Upstate Medical University in Syracuse, NY.

Beyond B12

Their paper, published in the journal Nutrition​​, notes that, “In the eyes of regulatory agencies, dietary requirements for cobalt are considered to be determined by dietary requirements for vitamin B12,”​ they wrote.

B12, also known as cobalamin (reflecting it’s cobalt fraction) is needed for blood cell formation, for healthy brain and nervous system function, as well as in DNA synthesis, fatty acid synthesis and energy metabolism. It is generally assumed that if you get enough B12 you are getting enough cobalt. However, Drs Glade and Meguid argue that the mineral may play important biological roles “independent of and in addition to its sequestration within vitamin B12 molecules.”​

Antioxidant and anti-inflammatory

Citing studies that go back to the 1960s, Glade and Meguid highlight data which shows that small amounts of cobalt have the potential to stimulate antioxidant defenses in humans as well as suppress inflammation.

It’s a controversial claim since cobalt and cobalt compounds are classified as ‘possibly carcinogenic’ by the International Agency for Research on Cancer (IARC), a division of the World Health Organization (WHO).

Glade and Meguid however, argue, that the IARC conclusion was “based on extreme intakes in animal experiments,” ​and that there was “no evidence of human carcinogenicity of cobalt and cobalt compounds.”​

The authors report that a number of investigations and expert panels have been conducted to confirm the safety of cobalt dietary supplementation in humans. One such investigation, published in 2004 by the US Agency for Toxic Substances and Disease Registry, concluded that the long-term minimal risk level for oral cobalt in adults is 10 micrograms per kilogram of body weight daily.

Get it from food

Cobalt – separate from vitamin B12 – is not generally included in supplements and there is some question over how well absorbed it is in mineral form in any case. The claim of cobalt carcinogenicity is not related to cobalt found naturally in everyday foods. It is equally possible that the cobalt content of these foods contributes to their health benefits.

Meat, liver, kidney, clams, oysters, and milk all contain some cobalt. Ocean fish and sea vegetables also contain cobalt. Land vegetables, as well, have small amounts, though as our soil becomes increasingly cobalt deficient levels in plant foods are reduced. Some cobalt is available in nuts, oats, legumes, spinach, cabbage, lettuce, beet greens, dates and figs.

Including more cobalt-containing foods in your daily diet should ensure you get enough.

Caffeine is one of the most researched substances reported to help athletes perform better and train longer and harder.

As a result, professional and amateur sportspeople often take it as a performance-enhancing “ergogenic” aids for a wide range of activities. These include intermittent exercise such as football and racket sports, endurance exercise such as running and cycling, and resistance exercise such as weightlifting.

But while most research looks at the effects of pure caffeine consumed as tablets with water, in the real world most people get their caffeine from coffee, energy drinks or other products like special gels or chewing gum. So will drinking a cup of joe before your workout actually make a difference? The answer could depend as much on your genes as what kind of coffee you’re drinking.

Scientists think caffeine affects the body chemical adenosine, which normally promotes sleep and suppresses arousal. Caffeine ties up the receptors in the brain that detect adenosine and so makes it more alert.

But it may also increase stimulation of the central nervous system, making exercise seem like it involves less effort and pain. In high-intensity activities such as resistance training or sprinting, it may increase the number of fibres used in muscle contractions, meaning movements can be more frequent and forceful.

Faster, higher, stronger

Research has shown that pure caffeine can help endurance athletes run faster and cycle for longer. It can help footballers to sprint more often and over greater distances, and basketball players to jump higher. It can help tennis players and golfers to hit the ball with greater accuracy. And it can help weightlifters lift more weight.

The evidence for caffeine’s effects on sprinting is more mixed. Limited improvements have been found for events lasting under three minutes. But for races of around ten seconds, caffeine can improve peak power output, speed, and strength.

An increasing number of studies have also shown that coffee can be used as an alternative to caffeine to improve cycling and competitive running performance, and produce similar results similar to pure caffeine. In fact, coffee may even be more effective at improving resistance exercise than caffeine alone. Similarly, drinking energy drinks containing caffeine before exercise can improve mental focus, alertness, anaerobic performance and endurance performance.

But drinking coffee isn’t like taking a measured dose of caffeine. The amount of stimulant in a cup, and so how it affects you, will depend on the blend of coffee and how it is brewed.

Studies have shown consuming either 0.15g or 0.09g of caffeinated coffee per kilogram of body weight can improve performance. So a dessert spoon of coffee granules rather than a traditional teaspoon is probably best.

It’s also worth bearing in mind that each piece of research shows caffeine improves athletic performance of a group of people as a whole. But we also know that genetic factors have a big influence on our responses to caffeine and not everyone reacts in the same way. This means consuming caffeine won’t necessarily improve your performance.

Potential downsides

In fact, you could end up feeling nauseated and jittery at a time when, if you are competing, you are already feeling anxious. And, as caffeine’s effects can linger for up to five hours, taking it too late in the day could disrupt your sleep, which is a big factor in health and fitness in general. This means it’s important to practice with caffeine during training sessions or friendly fixtures before using it for an important event.

Some have also suggested that you should abstain from caffeine in order to enjoy a better effect on your performance when you consume it for exercise. But maintaining your normal intake will prevent any possible withdrawal symptoms and still provide benefits if caffeine is taken before exercise. Its effects peak between 30 and 75 minutes after ingestion.

Finally, it’s a a commonly held belief that caffeine is a diuretic that will lead to dehydration because it makes you produce more urine. But a number of studies have shown that this isn’t the case with moderate amounts of coffee, cola or any other caffeinated beverage, which help keep you hydrated like any other drink.

• Neil Clarke is a Principal Lecturer in Sport and Exercise Science at Coventry University, Coventry University.
• This article was originally published on The Conversation website. It is reproduced here with permission and with a short summary for ease of reading.

Recently researchers from Stanford University School of Medicine took 609 men and women aged 18 to 50 and randomly split into two dietary groups – low carbohydrate or low fat – and followed them for a year.

Overall those who ate plenty of vegetables and whole foods lost significant amounts of weight over that time without restricting the quantity of food that they consumed. The low-carb participants lost an average of 13 pounds, while the low-fat group lost an average of 11.7 pounds. Essentially, both diets worked equally well and both groups also saw improvement in other health factors such as blood pressure and body fat.

That may not be what those who love the polarized low-fat versus low-carb debate would like to hear, but it’s a win for those who prioritise the bigger picture of nutrition.

Nutrition nutrition nutrition

Interestingly those results weren’t necessarily what the researchers were looking for when they started.

The original goal of the study, which is published in JAMA, was to compare how overweight and obese people handled each type of diet, but both groups were also encouraged to prioritise better quality food over processed options.

The researchers were also looking at genetics and insulin, seeking to discover if these nuances of biology would encourage an individual’s body to favour a low-carbohydrate diet or a low-fat diet. In fact, results showed no link between a person’s individual genetic make-up – or their insulin secretion level – and how much weight they lost.

Making better choices

It’s not that calories don’t matter, say the scientists. Participants in both groups were eating less by the end of the study. It’s more that calories shouldn’t be the main focus when it comes to weight loss.

What’s key, said Christopher Gardner, PhD, professor of medicine and the lead author of the study, was emphasising that these were healthy low-fat and low-carb diets: A soda might be low-fat, but it’s certainly not healthy. Lard may be low-carb, but an avocado would be healthier.

“We made sure to tell everybody, regardless of which diet they were on, to go to the farmer’s market, and don’t buy processed convenience food crap. Also, we advised them to diet in a way that didn’t make them feel hungry or deprived – otherwise it’s hard to maintain the diet in the long run,” he said.

“We wanted them to choose a low-fat or low-carb diet plan that they could potentially follow forever, rather than a diet that they’d drop when the study ended.”

We’re all different

“We’ve all heard stories of a friend who went on one diet – it worked great – and then another friend tried the same diet, and it didn’t work at all,” said Gardner. “It’s because we’re all very different, and we’re just starting to understand the reasons for this diversity. Maybe we shouldn’t be asking what’s the best diet, but what’s the best diet for whom?”

Perhaps the biggest takeaway from this study, Gardner said, is that the fundamental strategy for losing weight with either a low-fat or a low-carb approach is similar. Eat less sugar, less refined flour and as many vegetables as possible. Go for whole foods, whether that is a wheatberry salad or grass-fed beef.

“On both sides, we heard from people who had lost the most weight that we had helped them change their relationship to food, and that now they were more thoughtful about how they ate,” said Gardner.

Most recently a class of chemicals used in many industrial and consumer products was linked with greater weight gain after dieting, particularly among women, according to a study led by Harvard T.H. Chan School of Public Health.

The chemicals – perfluoroalkyl substances (PFASs) – have been linked with cancer, hormone disruption, immune dysfunction, high cholesterol, and obesity.

The study, published in PLOS Medicine, also found that higher blood levels of PFASs – known as ‘obesogens’ because they may upset body weight regulation – were linked with lower resting metabolic rate (RMR), or slower metabolism after weight loss. Metabolism refers to the chemical processes in the body that convert energy from food, commonly known as “burning calories.”

People with a lower RMR, or slower metabolism, burn fewer calories during normal daily activities and may have to eat less to avoid becoming overweight.

“Obesogens have been linked with excess weight gain and obesity in animal models, but human data has been sparse. Now, for the first time, our findings have revealed a novel pathway through which PFASs might interfere with human body weight regulation and thus contribute to the obesity epidemic,” said senior author Qi Sun, assistant professor in the Department of Nutrition at Harvard Chan School.

Pervasive chemicals

PFASs have been used for more than 60 years in products ranging from food wrappers to clothing to pots and pans, and studies have shown that they’ve contaminated drinking water near industrial sites, military bases, and wastewater treatment plants. These chemicals can accumulate in drinking water and food chains and persist for a long time in the body.

The researchers analyzed data from 621 overweight and obese participants in the Prevention of Obesity Using Novel Dietary Strategies (or POUNDS LOST) clinical trial, which was conducted in the mid-2000s.

This unique trial tested tested the effects of four heart-healthy diets on weight loss over a period of two years. Researchers looked at the possible connection between the amount of PFASs in participants’ blood as they entered the study and their weight loss or gain over time.

Women particularly vulnerable

During the first six months of the trial, participants lost an average of 6.4 kg, but regained 2.7 kg over the course of the following 18 months. Those who gained the most weight back also had the highest blood concentrations of PFASs, and the link was strongest among women. On average, women who had the highest PFAS blood levels (in the top third) regained 1.7-2.2 kg more body weight than women in the lowest third.

In addition, the study found that higher blood concentrations of PFASs were significantly associated with lower resting metabolic rates.

“We typically think about PFASs in terms of rare health problems like cancer, but it appears they are also playing a role in obesity, a major health problem facing millions around the globe,” said study co-author Philippe Grandjean, adjunct professor of environmental health at Harvard Chan School. “The findings suggest that avoiding or reducing PFAS exposure may help people maintain a stable body weight after they successfully lose some weight, especially for women.”

How to lower your exposure

PFAS are used in many consumer products. They are used in food packaging, such as fast food wrappers and microwave popcorn bags; waterproof and stain resistant fabrics, such as outdoor clothing, upholstery, and carpeting; nonstick coatings on cookware; and cleaning supplies, including some soaps and shampoos.

People can be exposed to these chemicals (and may others which also have an obesogenic effect) in house dust, indoor and outdoor air, food, and drinking water.

Once they are in the environment, for instance in the water supply they are very difficult to avoid. As consumers we can take a stand against PFASs by refusing to purchase products containing PFCs, such as:

• Packaged foods. Stay away from greasy or oily packaged and fast foods, as the packages often contain grease-repellent coatings. Examples include microwave popcorn bags, french fry boxes and pizza boxes.
• Stain- and water-resistance treatments. Avoid furniture and carpets marketed as ‘stain-resistant’, and don’t apply finishing treatments such as Stainmaster to these or other items. Choose alternatives to clothing that has been treated for water or stain resistance, such as outerwear and sportswear. Other products that may be treated include shoes, luggage, and camping and sporting equipment.
• Personal-care products. Avoid personal-care products made with Teflon (look for PTFE on the label) or containing ingredients that include the words ”fluoro” or ”perfluoro.” PFCs can be found in dental floss and a variety of cosmetics, including nail polish, facial moisturisers, and eye make-up.
• Teflon or non-stick cookware. Many cook find non-stick cookware a boon but it can be dangerous. If you choose to continue using non-stick cookware, be very careful not to let it heat to above 450ºF (230ºC) as this releases perfluorinated chemicals into the air and into food. Do not leave non-stick cookware unattended on the stove, or use non-stick cookware in hot ovens or grills. Discard products if non-stick coatings show signs of deterioration.

For more on obesogens see our article Programmed to be Fat?