It is an almost universally held belief that people who are overweight just need to eat less and/or do more. The idea that eating less will make you weigh less assumes that the body cannot and does not adjust. It can and it does.
To think that if you eat 500 fewer calories the body will give up 500 calories of fat, to make up the difference, is the ultimate naivety in the world of dieting. The body is not a machine that converts calories into fat.
The idea that a reduction of 500 calories leads to the body giving up 500 calories of fat assumes that neither the BMR requirement (1,500 calories) nor the additional requirement (500 calories) change. In reality both change.
Think about it – you eat less food and they basial metabolic rate adjusts to maintain homeostasis.
The exact same applies for doing more. If you think that you can eat the 2,000 calories needed for the day and then try to do 500 more calories worth of exercise, with the body making no adjustment elsewhere, you are wrong.
Furthermore, exercise and BMR require quite different calories. Exercise is arguably best fuelled by carbohydrate (it provides glucose quickly for the body to use). BMR activities need fat, protein, vitamins and minerals. Carbohydrates can be useful for the vitamins and minerals they provide, but the macro nutrient, the carbohydrate itself, can only be used for energy, or fat making – not cell repair and fighting infection. Hence – if you eat 1,500 calories of carbohydrate (as the average citizen of the developed world currently does) – it can’t be used for body maintenance – you need to burn if off down the gym or you will gain weight.
Dr. Zoë Harcombe PhD Clearly Explains The Problems With Curent Healthy Eating Guidelines
In a study of formerly obese people, researchers at the University of Florida found that virtually all said that they would rather be blind, deaf or have a leg amputated than be obese again. That is the extent of our desire to be slim and yet two thirds of people in the UK, USA and Australia are overweight and one quarter obese. Why?
To be slim, to achieve the thing we want more than our sight, hearing, or mobility, we are told that we just need to “eat less and/or do more.” Quite specifically, the advice is “One pound of fat contains 3,500 calories, so to lose 1lb a week you need a deficit of 500 calories a day.” (ref 2)
So, why don’t we just follow the advice? Why on earth do we have an obesity problem, let alone an epidemic, when we so desperately want to be slim?
Busting Myths about Nutrition