Although the mechanisms of this regulation are probably many and varied, the control they exert is extremely precise. It seems that the number of extra calories taken on after exercise closely matches the amount expended, particularly for people engaging in high levels. This would suggest that without accurate calorie control and the ability to resist hunger over several days, exercise is not a good strategy for weight loss , though that doesn’t mean it’s not good for your health.
Even though appetite control after exercise is extremely accurate, unfortunately it does not return the favour when we overeat. As most of us will know, physical activity does not go up after a huge takeaway, even when observed over long timescales. So when we eat too much, our bodies are likely to ensure that any excess calories are stored, rather than encouraging us to run around and burn them off.
To make things worse, Ancel Keys’ Minnesota starvation experiments showed that when calorie intake is reduced, physical activity decreases. This is just one of the irresistible effects of our hunger hormones. So when we eat less, we will be naturally inclined to run a little slower, take a sneaky shortcut, drive rather than walk, or give a little less on the football pitch. As usual, our body fights weight loss in any way it can. And the less you eat, the harder it will fight.
Perhaps worst of all, when we decrease our physical activity, we do not seem to compensate by dropping our calorie intake. So if you are currently exercising regularly and suddenly stop for some reason, your appetite and habits will cause you to eat the same number of calories that you always have. When this happens, most of the excess you take in will be stored as fat. When regular runners cut their distance down for a period of time, they quickly gain weight. And even when they return to running their original distances, the extra pounds often fail to shift. This is one of the reasons why many professional boxers end up going to seed so quickly after retiring – it is an unavoidable consequence of our biology.
So, if you’re looking for immediate effects, the depressing truth about exercise is this:
- If you are fat, exercising will not automatically cause weight loss, because you will have a strong urge to eat more.
- If you eat too much, your body will have no urge to burn off the extra calories.
- If you eat too little, you will automatically start to move less to prevent weight loss.
- If you exercise regularly, you’d better not stop, because if you do you’ll end up getting fat.
MORE GLOSS: The Angry Chef - "Free-from is not the same as healthy"
Anyone who has ever run on a treadmill will know another depressing truth about exercise. Even when it really hurts, it does not burn off that much energy. Depending on your weight and speed, a half hour run will probably burn 300–400 calories. And yet a 48-gram Snickers bar contains around 250 calories. So it does not take much delicious, convenient snacking to completely negate any impact of that hard-fought run, especially when the calorie compensation occurs over days rather than hours. This has led many, including the low carbohydrate diet advocates Aseem Malhotra and Tim Noakes, to claim that ‘you can’t outrun a bad diet’.
But in reality, things are not quite so simple. Dr David Nunan is a senior research fellow at Oxford University who studies the role of physical activity in the prevention of lifestyle-related health conditions. He told me:
“You do have to do a lot of movement to use up 500 calories, and the headline grabber is that there is no benefit of exercise. Studies show that twenty minutes of daily exercise has no effect on visceral fat, but most of these are based on a version of walking. The studies look at levels of exercise that are within reach for people, but generally it is not enough. The conclusion from these studies should be ‘regular people are unlikely to lose weight with a typical amount of a common type of exercise’. And that’s if folk actually did the exercise they said they did. Supervised studies work better because it’s more likely the exercise will actually get done but the reality is that getting people who have never exercised before to do enough, or hard enough, consistently, is difficult to say the least. But even the little exercise they do can be of some benefit. The majority of studies show that when it comes to weight loss, diet and exercise beats diet alone. It’s just that diet has a bigger effect.”
This view might seem at odds with the evidence that we eat more to compensate for extra calories burned during exercise. But this is perhaps because we only think about weight gain in terms of calories in and out. When it comes to exercise, although it might not help us get thin in the short term, there is good evidence that over longer periods, it can make a huge difference.
There are many potential reasons why this might be the case. Exercise programmes have been shown to modify long-term regulation of appetite hormones, helping to increase perceived fullness after meals and making weight maintenance much easier. There is a suggestion that increasing physical activity might be one of the few things that can help to alter our bodies’ set point weight downwards, so hugely increasing the chance that long-term weight maintenance might be possible. If this is true, engagement in regular exercise could help free people from the misery of constant dietary failure and the endless cycle of yo-yo dieting.
For this reason alone, dismissing the role of exercise when it comes to weight loss, or claiming that ‘you can’t outrun a bad diet’, is a dangerous and thoroughly irresponsible message. It will only encourage people to abandon exercise as futile, pushing them to engage in more and more restrictive diets.
Because exercise has little effect on initial weight loss, its importance is frequently overlooked. But the truth is, almost anyone can lose weight in the short term. That is the easy part and only requires people to eat a bit less for a while. It is keeping any lost weight from returning that is so difficult, and exercise seems to be the one thing that can narrow your odds.
Dismissing the importance of exercise is also likely to exclude people from one of the most powerful and effective lifestyle interventions that we know of. Exercise has many extraordinary benefits beyond its effect on the body’s set point weight. It can reduce the odds of developing cardiovascular disease and type 2 diabetes , and can improve many aspects of mental health , including some that increase the risk of obesity.
When people exercise while dieting, it improves their body composition, with more muscle and less fat under the skin. It also seems that exercise is better at reducing visceral fat than diet. Visceral fat is thought to be a much more powerful predictor of morbidity than BMI.
MORE GLOSS: Why stress might be giving you visceral fat
This all suggests that although the effect of exercise on immediate weight loss might be limited, it is actually far better than diet at improving our health. And for all of the many benefits, evidence seems to indicate that the more exercise people can manage, the greater and more positive the changes they are likely to see. And for those with the most severe cases of obesity, it actually seems that the benefits of exercise can be even greater, reducing many of the risks of excess weight.
Weight is seen as the only measure of health, when in reality it is a poor indicator
Because of the way we confuse fatness, physical appearance and wellness , exercise is too often dismissed. Weight is seen as the only measure of health, when in reality it is a poor indicator. And so exercise is frequently cast as a pointless waste of time. When dieters see that it has no immediate effect on the scales, they assume it is not helping. In our obsession with shifting pounds, we are ignoring one of the most important things we can do to improve our health.
There’s just one problem. When it comes to exercise, we’re really shit at doing it.
THE EXERCISE PROBLEM
Weight management guidelines often suggest that people who need to lose large amounts should engage in around sixty minutes of exercise daily. But studies have shown that the number of obese people who actually manage to achieve that as part of a weight management programme is virtually zero. It appears that the recommendations are impossible for any real-life human being to achieve, which might lead us to question their usefulness.
Of course, you may think that fat people just need willpower. But can it really be the case that every single one of them is too weak-willed to comply? If you are thin, do you really consider every fat person you have met to have less willpower than you do?
Presuming we can safely reject the idea that all fat people are lazy, this lack of compliance might indicate that something else must be going on. Could it be that the same hormone pathways that drive people to overeat also reduce their ability to perform significant exercise in a long-term, sustainable way?
It certainly seems that this is, at least in part, the case. Obesity and sedentary behaviour are strongly and consistently linked. Remember how powerful the hormonal drivers are, nearly impossible to resist in the long term. These pathways do not just drive appetite, they also regulate every aspect of our energy expenditure, a significant part of which is exercise. Perhaps obese people have an inbuilt disadvantage when it comes to getting moving, the power of which the rest of us cannot imagine. And maybe the success of those people who manage to exercise and keep the weight off is because they have weaker hormonal drivers. Perhaps the ability to exercise is an effect experienced by people who find weight loss easier, rather than a cause of them being able to do so.
In reality, these effects are thought to be bi-directional, and likely to vary between individuals. So for some people, exercise will help them lose weight more easily. But others will be naturally more inclined to lose weight, while also finding exercise easier to maintain.
And there are other reasons why overweight people might struggle to exercise. Gyms, dance classes, running tracks, football pitches and tennis courts are often places where fat people are not made to feel comfortable or welcome. In researching for this book I collected many stories about weight discrimination. Some of the most unpleasant and depressing were connected to exercise and activity. I heard about people being openly laughed at and abused while running or cycling. Grown men reduced to tears, hiding in fear of looking ridiculous in newly purchased sports gear. Confident and high-achieving women told me how they were terrified of walking into a gym class, hiding away in their car for an hour before returning home in shame.
MORE GLOSS: 9 ways to overcome your fitness fears
Exercise has extraordinary benefits. It can be a source of real pleasure and greatly enrich our lives.
If you move your body regularly and get pleasure from it, be happy you have found that space. It has more benefits than anything else we can do in our lives and is a million times healthier than any restrictive weight loss diet.
But we must also try to accept that exercise will not be for everyone. Some will never be able to find a type of physical activity they can enjoy or maintain. Willpower alone will not keep you at the gym, and if you cannot find pleasure in movement, then it is unlikely you will last at it for long. For others, the stigma and traumatic associations will be too powerful, and it will not be worth the stress that these create. Injuries or disability might make all but the most tentative movement dangerous and painful.
So although I would strongly encourage everyone to get as much movement into their lives as they can, I appreciate that for some this will not be possible. We all need to try to lead the best lives we can, and no one should be made to feel guilty about things they cannot do. Because although a lack of exercise might cause you some problems down the line, I guarantee that feeling guilty about it will fuck you up twice as quickly.
An edited extract from The Truth About Fat by Anthony Warner published by Oneworld Publications from £7.99. Buy your copy here .
Follow Anthony on Twitter at @One_Angry_Chef .