If you eat more fat or sugar than your basal metabolism and your activities require, you will gain weight. But the basal metabolism vary between individuals. Some individuals have a decreased basal metabolism. Burning of fat is an important component of the basal metabolism. If the basal metabolic activity is decreased, a person will gain fat more easily.

A possible cause of obesity and low basal metabolism is reduced secretion of the hormone thyroxine and other hormones from the thyroid gland, because these hormones regulate and mostly increase the basal metabolism.

Other possible causes are lack of vitamins and minerals, like vitamine B6 ( pyridoxine ), magnesium and chromium, or a wrong mix of fatty acids in the diet, with too low content of essential unsaturated fatty acids.

When a person tries to slim off the fat, the body may lower its metabolism even more, making it difficult to take off fat. This is partly a kind of defence mechanism against starvation that was of use in earlier days when the food supply was unsecure. But it also is due to lack of nutrient caused by the slimming process. When the food intake is lower, the body gets even less of some essential nutrients that it needs for its metabolic activity.

When a person gains weight, this is done in three ways. It partly happens by filling the fat cells by fat, partly by filling the fatty cells with water and partly by increasing the number of fat cells. The proliferation of fatty cells most easily happen in early childhood, in the puberty and if the gaining of fat is very rapid.

The increased number of fat cells is difficult to get rid of, and since each cell tend to take up fat and protect the fat from being broken down, those cells make it difficult to slim away the excessive fat again. These cells also acts like a sack with a certain volume, and when the fat goes out, they tend to be filled with water instead. By the slimming process, the cell membranes of the fat cells need a period to shrink, so they cannot contain so much water any more, before essential weight reduction occur.

By knut Holt