“The best way to lose weight, believe me, is to eat less,” Boris Johnson said, defending the government’s food strategy after proposals for a salt and sugar tax were ignored.
With that “trust me,” the Prime Minister struck a chord with serial dieters: What parts of the vast smorgasbord of advice out there should we follow to ensure our health and happiness?
Along with the recent introduction of calories on restaurant menus, it can feel like we’re being embarrassed to stop eating altogether.
For Professor Tim Spector, the epidemiologist at King’s College London, celebrated for his work with identical twins, as well as diet and the microbiome, all of the above represents a step backwards in the public understanding of how humans respond to and process food.
“For the past 100 years, we’ve been obsessed with calories, and it’s really stopped us from thinking about anything else,” says the 63-year-old author of The Diet Myth and Spoon-fed. He has worked hard to change that thought.
When The Diet Myth was published in 2015, few people had any idea of the role that the estimated 100 trillion microbes in our gut play in our digestive system. Spector’s work has helped put kefir in our fridges and kimchi in our jars. Through the Zoe Project, the world’s largest nutritional research, he has encouraged all of us to work together and analyze our unique gut, blood fat and blood sugar responses.
Today, however, his main myth target is that calories are a convenient way to track our diet. Not only are calorie estimates often less accurate than we’d hope, Spector’s studies of twins have shown that people vary wildly in how much energy they get from a particular food.
The daily allowances for men and women are not based on hard data, according to Spector. So I ask him: what should we strive for? Even asking the question, he says, gives credence to the idea that there is a perfect figure. “If it were only 1900, would that make a difference? No, it wouldn’t.”
And when people are told to avoid high-calorie foods, Spector says advice can be taken to encourage consumption of low-calorie drinks and low-fat foods. “That’s why we support this multi-billion-pound diet industry of low-calorie shakes and Weight Watchers, and all that other stuff.”
So, what other diet myths are we swallowing, according to Professor Spector?
Myth: Exercise to lose weight
Exercise does require energy, but our metabolism adapts to that loss by storing more energy as fat the next time we eat.
Our bodies are programmed to keep our biology stable, also known as homeostasis, so if our energy levels change drastically with a lot more exercise and less food, our metabolism will respond by slowing down weight loss and eventually turning it back on very quickly when we eat. go back to normal activity and food – that’s what we see in yo-yo dieters regaining all the weight they initially lost. “To say that exercise alone is a good way to achieve a healthy weight in the long run is complete nonsense,” says Prof. Spector.