Under 20: underweight
Over 40: dangerously obese
One of the best and most convenient ways to measure body fat is to use an electronic machine that uses bioelectrical impedance. Sound confusing? It’s simple to understand. An electric current is passed though the body and the machine measures how long it takes for the current to come out, providing you with a measurement of your total body fat. Lean tissue is a much better conductor of electricity than fatty tissue, so that machine is able to measure the percentage of fat in the body.
These are available for use in the home, look just like ordinary scales and can also be used to weigh yourself normally.
The causes of weight gain
There are many reasons why you may gain weight and the cause may not be one factor but a combination of a number of different ones.
Yes, one of the main causes of weight gain is dieting. Dieting makes you fat. As you reduce your food intake to lose weight, your body put itself on ‘famine alert’. It gets the impression that food is scarce and therefore it slows down your metabolism to get the best use of the small amount of food it is receiving.
When you say you want to lose weight, what you actually want to lose is fat. If you lose weight rapidly, almost 25 percent of that weight loss can be made up of water, muscle and other lean tissue.
The reason for this is that your body is actually programmed to hold on to fat. So in times of what your body considers to be a ‘famine’, it will actually go as far as breaking down muscle and losing water in order to hold on to its fat reserves. Faddy diets suggest that you can lose up to 10 pounds in a week, but remember this: it is physically impossible to lose more than 900g (2lb) of body fat in a week.
Furthermore, if you lose weight quickly by restricting your intake and then go back to eating normally, a much higher percentage of the food you eat is laid down as fat. Why? Because your body wants to build up extra fat stores, in case this type of famine occurs again. There’s also the question of metabolism. When you crash diet, your metabolism slows down to conserve energy and make the most out of the small amounts you are eating. What happens when you go back to eating normally? Well, everything you eat is being dealt with at a much slower rate and more fat is stored.
Too much food and not enough exercise
This is the obvious reason, because if you eat more than you burn off then you are going to gain weight. The idea has been that if the number of calories going into your body is less than the calories being used up by bodily activity and exercise, then you will lose weight. Nowadays, we know that the type of calories is also an important factor in this equation. In other words, you need to consider what type of calories you are eating – whether they come in the form of fat, carbohydrates or protein.