Myth 2: Metabolism slows with age
Been blaming your tight waistband on advancing age? Last year, a research team at Duke University published a paper that poured cold water on that theory. The team looked at the average daily calories burned by 6,400 people, ranging in age from new-born to 95, as they went about their daily lives around the world.
If you are imagining that the teens and twenty-somethings burn through calories the fastest, you are not alone. But you are wrong. “We can’t blame our metabolism for the weight we gain in middle age,” says Herman Pontzer, study lead and author of Burn: The Misunderstood Science of Metabolism. “The calories we burn each day are incredibly stable all through adulthood, from our 20s up until we hit about 60.”
From our 60s onwards, our metabolism does slow, but only at a rate of 0.7 per cent a year. So there goes that excuse.
Myth 3: We all process calories the same way
Remember that infuriating friend who claims to eat like a horse while maintaining the figure of a rake? Well, it turns out that she may not be fibbing. In 2019, the largest ongoing scientific nutrition study of its kind, led by an international team of scientists including researchers from King’s College London revealed that individual responses to the same foods are unique, even between identical twins.
The researchers measured how blood levels of markers – sugar, insulin and fat, for example – change in response to specific meals, while tracking data on activity, sleep, hunger and gut bacteria in thousands of participants in the US and UK (60 per cent). of them twins).
The results revealed a wide variation in blood responses to the same meals, suggesting that personal differences in metabolism, caused by factors such as the gut microbiome and exercise, are just as important to our health and waist bands as the nutritional composition of our foods. “It depends on who you are, of course,” says Yeo, “and it is not 50/50 exactly, but both aspects play a substantial role.”
The moral of this myth? You may not be able to eat more or, unfortunately, less of the recommended calorie intake before you gain weight.
Myth 4: Low-fat foods are best if you want to slim down
Fats provide more than twice the calories per gram of carbohydrates. So stick the low-fat yoghurt in your basket next time you’re shopping… right? Actually, no.
“What consumers assume is that when something’s labeled low-fat, it will be low calorie, but that’s often not the case,” says Johnstone. “Just because it’s low fat doesn’t mean it’s low calorie, that food product will need to contain other macro-nutrients.”
Manufacturers often increase the amount of sugar in their low-fat products to compensate, leading to blood-sugar spikes and cravings. On the other hand, healthy fats, like those in nuts or avocado, help to keep us feeling full for longer. Reach for low-fat alternatives and you may also end up reaching for more snacks later.
Myth 5: Calorie counting keeps weight off
In July, a survey published in the British Journal of Health Psychology brought a crumb of comfort to those who struggled to ignore the rumblings of our stomach as elevenses approaches.
Over 6,000 young adults across eight countries were quizzed about their self-esteem and body-mass index. Researchers then compared to three eating styles: intuitive (eating when you feel hungry), emotional (or “eating your feelings”), and restrained (restricting calories to lose or maintain weight). Little surprise that those who come intuitively tended to have higher self-esteem. They also, however, appeared to have a lower weight.
“The problem with ‘weight-control strategies’, or dieting, is that they typically require you to ignore your physical cues of hunger and satiety,” explains lead researcher Dr Charlotte Markey, from Rutgers University in New Jersey.
“This isn’t a good long-term strategy. Those cues are there for a reason – to keep you alive! This doesn’t mean that people should just eat anything at any time or all the time. But being hungry is miserable and not sustainable.”
In fact, a 2010 study from the University of California found that counting calories the rise of a stress hormone linked to excess abdominal fat. “Cutting your calories increases cortisol,” explained study lead A Janet Tomiyama. “We think this might be one reason dieters tend to have a hard time keeping weight off in the long-term.”