Dieting myths

"He/she eats what they like and never puts on weight"

It’s just about impossible to compare our own diet with someone else - we just don’t see everything someone else eats over a whole day or week or month. It’s also important to remember that we don’t always see all aspects of someone’s lifestyle - do they walk a lot and use stairs, what sort of job do they have, what do they do when they get home in the evening or in their spare time, how do they travel around? And remember we all have different needs and perspectives - what looks like a lot to us, may not be too much for someone else.

"I’m only overweight because of my hormones"

A small minority of people have a thyroid problem causing weight problems, but they’re likely to have a range of other symptoms that means that this condition will be detected, diagnosed and treated.

"It’s my genes" 

Lots of work is being done on the link between our genes and obesity. While part of our metabolic rate and the way our fat is deposited may differ between us because of genetic differences - these differences are very small. Also, the increase in obesity over the past 20 years cannot possibly be explained by differences or changes in our genes. One thing's for certain, there’s not going to be one gene to explain overweight and obesity, or the tendency to put on weight.

"I have a slow metabolism" 

Our basal metabolic rate - or BMR - is the minimum amount of energy our bodies need to keep us alive (e.g. breathing, keeping all the vital organs functioning, and keeping us at the right temperature). Anything else we do - like sitting up, eating, talking and walking - uses energy over and above our BMR. In adults, the BMR depends mainly on their body weight and the amount of lean tissue they have. In general, but not always, men have higher BMRs than women, and as we get older our BMR gradually decreases. BMR can differ between people who are very similar in all respects - ten people of the same sex, age, weight and height will have differences in BMR of about 8%. The most important thing is that the bigger someone is the higher their BMR is. A man or woman weighing 12 stone will never have a BMR that is less than a man or woman who weighs 8 stone.

"Dieting slows down your metabolic rate"

This is true to some extent. When our bodies are deprived of food for a day or more, our metabolic rate slows down to save energy. But as soon as we start eating again, our BMR returns to it usual value. Small drops in BMR should not be used an excuse as to why diets fail. If someone is a successful slimmer and has lost a significant amount of weight, they obviously will have a lower BMR than they did at their higher weight. But they will not have a significantly lower BMR than someone of the same sex, age, height and weight who has never been overweight.