Tracking our calorie intake has long been touted as the only sure path to weight loss. However, in a new book, obesity researcher Dr Giles Yeo (a geneticist with two decades’ experience studying obesity, based at the University of Cambridge, and author of Why Calories Don’t Count and Gene Eating) argues that we’ve been misled – and offers his alternative prescription.
Men’s Health: A reduced-calorie diet is generally considered the key to weight loss. But you argue that most diets fail. Why?
Giles Yeo: In a sense, the majority of diets do work. They get people to eat less, which means they lose weight. The problem is keeping weight off. The way we’re set up evolutionarily is that the brain hates it when you lose weight; it considers it a reduction in your chances of survival. So, your brain will drop your metabolism slightly, and it will make you hungrier (1). It’s worse with extreme diets. The weight comes back on even quicker.
What’s the alternative?
The only way to lose weight is to change the way you eat forever. You’ve got to put together a lifestyle strategy for keeping it off. It will always be difficult, and anyone who tries to tell you it’s easy is lying.
Why can’t calorie-counting be a part of what you call a “lifestyle strategy”?
Clearly calories do count to some degree. They reflect the energy content of a food. If I need
to reduce my intake, I can halve my portion of chips from 500 calories to 250 calories. That’s legitimate, because it’s the same type of food. What doesn’t make sense is blindly counting calories, because it makes a difference whether you’re eating 100 calories of celery versus 100 calories of sugar. People say all calories are equal.
Are they not? Nutritional benefits aside …
GY No. We process different foods very differently. The number on the packet does not equal the number of calories you end up using. What’s not reflected is the amount of energy it takes you to “get at” the calories. Something like fat doesn’t cost a lot to break down. It’s 97 per cent calorically available. Carbohydrates – wholemeal bread is 92-95 per cent available, and sugar is 95-97 per cent. The big difference lies in protein. For every 100 calories of protein, we absorb only 70 calories.
How much of a difference does that make?
It’s not a big difference from meal to meal. But over every single meal of your life, it will be. If you look at foods that aren’t high in quality, particularly ultra-processed foods, they tend to be low in protein and fibre, both of which are less calorically available (2). The amount of protein and fibre in foods is an easy marker of quality. It’ll make
you feel fuller, too.
So how do we make losing weight sustainable and not painful?
I can’t claim that it won’t sometimes be painful.
Then let’s talk about minimising pain. What advice would you give?
Concern yourself with the quality of the food you’re eating. Looking for ways to improve the quality of your diet will improve
your health, and if you focus on your health, your weight will sort
of take care of itself (3).
Many calorie-counters whose primary goal is weight loss would find that contentious…
Start by asking why you’re trying to lose weight. If it’s to look good, then what’s your definition of “good”? I want to look like Brad Pitt, but I don’t. You might not be totally happy with how you look, but are you healthy? Are you able to lift your child up? Are you able to cycle? Are you eating high-quality food? If the answer is yes and you can maintain your weight, then perhaps that’s what you should do.
Do you believe in a “set point” weight?
I usually refer to a set range. Say I lose half a stone [3.1 kilograms]. Keeping that off will require effort. But if I stay where
I am, there’s almost no effort. If you’re an MMA fighter, or a model, that’s different. For most of us, what we want is to be able to walk up the stairs or go for a run without feeling out of breath. Look, a lot of people do need to lose weight – I’m
not saying that they don’t. But a lot of people just need to be healthier.
You talk about combating weight stigma. Is that a hard line to walk, as your job is to study obesity?
As mature human beings, we should be able to hold two thoughts in our heads at once. Obesity is a problem. But then there’s blaming people who are suffering from that problem. Undoubtedly, the prevailing view is that our bodyweight is a choice. But our thermostats are set in different places, biologically (4). Some people think that they have more willpower, but we are just looking
at ourselves and projecting onto other people.
Your own guidelines seem relatively straightforward: enough protein, more fibre, less sugar and less meat.
It sounds boring, but it’s as close as I’m going to get to a plan. And it’s not a diet – it’s really just eating sensibly.
(1) Pennington Biomedical Research Center (2) Food & Nutrition Research (3) Stanford University. (1) Exercise habits are a better predictor of weight loss maintenance than a person’s diet. (2) In one study, two groups ate sandwiches with identical calories: one made using whole foods, the other processed. The former required 47 per cent more energy to digest. (3) Focusing on the quality of your food without counting calories can lead to greater weight loss. (4) Dr Yeo’s research suggests some of us are genetically 5 per cent less likely to be able to say “no” to excess food.
