June 30, 2016

The old dogma of ‘eat less and exercise more’ has finally been laid to rest, but will anyone be listening? Exercise for weight loss is simply not a good strategy. It helps, of course, but by itself it’s not enough.

This video summarises how we burn calories: through resting metabolism, the thermic effect of food, and exercise. Our resting metabolism takes care of the bulk of our caloric burn each day, so adding a bit of exercise doesn’t really do much to help weight loss.

This is not to say that you shouldn’t exercise. Not at all. The health, wellness and feel-good effects of exercise are extremely valuable and everyone should live an active lifestyle – through work, leisure, exercise and daily movement patterns.

Over 60 studies show that exercise is “pretty useless when it comes to weight loss”. According to researcher Kevin Hall, PhD, “Exercise isn’t a weight loss tool, per se. It’s excellent for health, it’s probably the best single thing you can do other than stopping smoking to improve your health, but don’t look at it as a weight loss tool.”

Exercise, for most people, counts for between 10% to 30% of energy use. Think of it this way: 100% of the calories you consume come from the choices you make, while only 10%-30% of the calories you burn come from your choices.

Exercise then contributes to a range of compensatory behaviours, both physiological and conscious.

  • It makes many people hungry, so they eat more.
  • It makes many people do less for the rest of the day.
  • As weight is reduced, resting metabolism reduces.
  • Many people over-estimate the effect of exercise, thinking that they can eat what they like as long as they exercise. A donut will not be walked off in 30 minutes.

All over the world, governments and health groups promote exercise as a way to lose weight, but the evidence simply doesn’t support this advice. It’s easier to recommend exercise than it is to adjust the food supply or official dietary guidelines. It’s easier to recommend an increase of exercise than it is to change people’s shopping and eating habits.

Many food manufacturers align their advertising with sports and activities, perhaps in an attempt to give their products the ‘health halo’ that exercise provides. The implicit idea is that you enjoy all the sugary drinks, biscuits or burgers you like, as long as you stay active. We know that marketing has the goal of selling products, not helping the health of the population, so let’s ignore the ads.

Many nutritionists and dietitians have the mantra of “everything in moderation”. This is often because they feel that making permanent change to eating habits is too hard for most people. If these experts think you can’t do it, chances are that you’ll believe it. If we’re being perfectly honest, it can be easy to justify eating (or drinking) just about anything we like if we live by this mantra: it just usually doesn’t help our weight or our health.

So while exercise will help you live a long and healthy life, don’t expect miracles for your weight loss efforts. You need to exercise, for sure, but unless you take control over what you eat and drink, weight loss will be an elusive goal.