Always knew that some people's calories are handled differently also age make a difference I could eat a horse when 20 and not put on weight . on the one hand they say its because someone at that age is very active.
But then say you'd need to exercise for 2 hours to run off a mars bar
They can't have it both ways.

A big comfortable Bentley or Rolls will drink up far more Gas than a Pinto
I'm in the Rolls Royce class so I need lots Fuel but have swapped Quantity to Quality


Scientists debunk decades-old theories on losing weight
By Jeremy Laurance, Health E


Dieting is harder than you think. If you cut out a chocolate bar each day you will lose only one-third of the weight that experts had thought. For decades, doctors have based their advice to those who want to lose weight on the assumption that cutting 500 calories a day will see the weight fall off at the rate of 1lb a week.

"This is wrong," Kevin Hill, of the National Institutes of Health in the United States, said. "It does not happen." The error has arisen because the calculation did not take account of changes in metabolism as weight falls. The body adjusts to reductions in energy intake (calories eaten) by slowing its energy output (calories expended). The result is that forgoing that daily chocolate bar containing 250 calories will lead to about 25lb of weight loss if it is sustained for three years, much less than the 78lb predicted by the old dieting assumption.

Related articles
UK fat alert: 26 million will be obese by 2030
Leading article: The case for a fat tax
Search the news archive for more stories
A more sophisticated measure of weight loss, which takes account of metabolic changes and of differences between fat and thin people, has been developed by Dr Hill and colleagues of the National Institute of Diabetes and Digestive and Kidney Diseases. It shows that heavier people tend to lose weight faster than lighter people on the same diet, though they will take longer to reach the target weight than those who weigh less to begin with.

Most people on a diet achieve their maximum weight loss after six to eight months and it has been assumed this is a natural "plateauing" effect, resulting from slowed metabolism. But evidence shows that people find it hard to stick to a diet for longer than six months and that is why they stop losing weight. Body-weight plateauing occurs much later, after two to three years.

There is nothing to choose between different diets that alter the fat, protein and carbohydrate balance, such as the Atkins diet that reduces carbohydrates, the researchers say. The body adapts rapidly to changes in these constituents with the result that all diets result in the same loss of body fat, at least in the short term. They said: "Little is known about the long-term effects."

It has been difficult to assess how closely people follow diets as research relies on self-reporting. The authors said: "Widepread past use of erroneous rules for estimation of human body-weight change have led to unrealistic expectations."