Move It & Lose It with Prof Trim

Forget the calculations. Just do it until it works.
Here’s a typical question I am asked: ‘Looking at calculations I’ve done on the food I eat and exercise I do, I can’t understand why I’m not losing more weight. What’s going on here?’


Dr Garry Egger aka Prof Trim

This is a common problem for many big people; and it’s something scientitis still puzzle over. Top American researcher Steve Heymsfield has been looking at this, and in an article in the American Journal of Clinical Nutrition (2007;85(2): 346-354) lists what he thinks are the reasons. You don’t need a science degree for the explanation, but it does get a bit technical.

If you burn food in a laboratory bomb calorimeter, you get a measure of the number of Calories (or kilojoules) in that food. A Calorie (yes, correctly spelled with a capital C but usually written as calorie) is the amount of heat energy required to raise the temperature of 1 g of water 1ºC. You can estimate roughly also the number of calories burned up carrying out different types of exercise. An 80 kg person walking for about a kilometre for example burns roughly100 calories. As 1 kg of fat is about 7000 calories, we can calculate, in theory at least, how much fat someone should lose if they eat X and expend Y calories.

Unfortunately, in real life, bodies don’t follow theories all the time. Once you take a physical calorie (food) into your body, or your body burns energy, what happens inside your body may not be the same as what happens inside mine: we are all a bit different. This is because changes can occur within our bodies to make each unit of food or exercise worth more or less than the actual ‘physics’ calories. For example, if a food speeds up metabolic rate in one person, it may result in more calories being burned than in another. For a big person, carrying extra weight means walking a set distance would use more calories than for a small person. Big people then may have different physiological adaptation than small.

That’s one possible explanation for why big people don’t lose as much as predicted. But there’s another, possibly more basic explanation. According to Steve: Big people under-report (without doing it consciously) their food intake and exercise expenditure. So no matter how honest you try to be with yourself, it doesn’t always work. So, forget the calculations. Just do it until it works.

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