Weight loss is 95% diet and only 5% exercise — doctor

As a weight management doctor, one of the most frequent questions I get asked is: “Why am I the only one in my family who is fat, when we all eat the same things?”

Some people are more prone to weight gain than others. Some are more responsive to exercise than others. Genetics loads the gun, but diet pulls the trigger.

This alone throws the calorie theory out the window. If a calorie is a calorie, why are some people ‘exempt’ from weight gain, if they are consuming the exact same food? When people go on 500 calorie diets, why do some lose more weight than others?

If a calorie is indeed a calorie, everyone should lose exactly the same amount of weight. This never happens. Not even in a controlled environment.

I looked after an obese client who ate, on average, 1,000 calories a day and had done so for many years. Not exactly what I would consider gluttony. Would I disbelieve her? Would I tell her to exercise more? No, and no.

Exercise for weight loss is another shamefully propagated misconception. Nearly all Big Food companies tell us that their products, such as soda, chocolate bars or sugary cereals, can be enjoyed “as part of a healthy lifestyle”.

Some slimming clubs have reward snacks that almost always consist of processed junk food, to ‘enjoy’ after a period of exercise. This is crazy.

If you are being given the wrong information, how are you expected to make the right choices?

To ‘create’ energy, you either burn stored fat or burn available or stored glucose. If the point is burning fat (to lose weight), this will never happen if you keep consuming glucose in the form of fruit or snacks.

One gets the feeling that the blame is being deliberately diverted away from the utter crap they are selling that is making us sick and fat, towards us. We are told it is our responsibility to exercise to maintain weight, regardless of what rubbish we put in our bodies.

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I need not remind you that Big Food and many weight loss franchises are obligated to their shareholders, not to you. If you are being given the wrong information, how are you expected to make the right choices?

Weight loss is 95 per cent diet, five per cent exercise. Put simply, you cannot outrun a bad diet. Exercise is fantastic for overall health, but really inefficient for weight loss. Most people (and many calorimeters on exercise machines) grossly overestimate calorie burn during exercise. The same is true for wearable fitness technology, as shown in this study.

Say you ‘burn 200 calories’ walking briskly for an hour on a treadmill. If you then consume a chocolate bar (230 calories) or a sugary sports drink after your workout, you will have effectively undone all your efforts, in the minute or two it takes to eat that snack or take that drink. Adaptation is the reason why exercise is relatively ineffective for weight loss.

Your exquisite body will also ‘fight back’ after exercise, particularly after long, intense exercise. Your body will often compensate by reducing your desire to move much, following your workout. Many of us have noticed just how little we want to voluntarily move after exercising.

It will also make you hungrier. Resisting the urge to eat will be nearly impossible. Believe me, biochemistry will always trump ‘willpower’. Then there are the injuries, which will leave you inactive for weeks. Those who exercise excessively could also lower their immune system temporarily. Have you ever experienced flu-like symptoms after a long run? Then you know what I’m talking about.

Sedentary behaviour is clearly not to blame for the obesity epidemic. Something else is making us fat.

Our weight is carefully regulated by hormones. Biochemistry and hormones drive all our behaviour, including our eating behaviour. Our weight has nothing to do with how much we eat or how little with exercise. Calorie balance does not control weight. Hormones do.

Insulin (the fat storing hormone) is the major hormone that drives weight gain. The other is Cortisol, to a lesser extent. Weight gain is mainly caused by high insulin, excessive cortisol, insulin resistance or a combination of all three. Identifying the right trigger for a particular individual is the key to weight loss.

If you are troubled by your weight and want to do something about it, find a weight management expert who understands that willpower is overrated. One who knows that weight has nothing to do with self-control. One who will treat you with the same empathy that all people deserve. It is entirely possible to naturally manipulate your hormones to shift the weight.

Dr Nyambura, a National Health Service (NHS) physician, is a London-based medical weight loss expert and the medical director of Insulean, a private metabolic and weight loss clinic.