When a body has lost a good number of pounds through effective dieting, several reactions conspire to put the weight back on. To understand them, you need to know that the buildup of fat reserves means that the body has surplus calories available in case of any future food shortage.
Fat was the simple solution nature came up with to conserve and store energy; it is the most concentrated form known in the animal kingdom (1 gram of fat = 9 calories). Nowadays, when food is completely and easily accessible, we may well ask ourselves what use storing fat is to our bodies.
But, again, you have to remember that our biological system was not designed for the modern world; it came into being at a time when access to food was hazardous and unpredictable and required struggle and hard work. Being fat was a precious survival tool for the first humans. The human body, whose biological programming has remained unchanged, still bestows the same importance on what it considers as its vital reserves and does not like to see them being plundered.
A body that is losing weight risks being left with no resources if there is the slightest interruption in its food supply. That is why it reacts—because it feels threatened biologically. All its reactions have one sole objective: to recover all the fat it has lost as soon as possible. Your body has three very effective ways of doing this:
• The first is to trigger hunger pangs and sharpen your appetite to encourage you to eat more; the more unsatisfying your previous diet was before you embarked on the Diet, the stronger this reaction will be.
• Your body’s second strategy is to reduce its energy consumption. If you earn less money, you tend to spend less. Biological organisms react in a similar way. This is why many people complain about feeling cold during weight loss diets; your body is using less energy to keep you warm.
The same goes for tiredness: when we feel tired, we avoid any unnecessary effort, excessive activity becomes difficult, and everything slows down. Memory and intellectual effort, which require a lot of energy, are also affected. The need for sleep and rest, which save energy, also increases. Hair and nails grow less rapidly. In short, in order to adapt to a long period of losing weight, the body goes into a kind of hibernation.
• Finally, the body’s third reaction is the most efficient and the most dangerous one, whether you are trying to lose weight or are already stabilizing, as it consists in assimilating the calories from your food more efficiently. An individual who ordinarily gets 100 calories from a slice of bread will end up, at the end of the diet, assimilating 120 to 130 calories from the same slice. Each morsel is sifted through, and everything possible is absorbed. This increase in calorie extraction takes place in the small intestine.
Increase in appetite, reduction in energy used, and maximum extraction of calories consumed all combine to transform the overweight body that has just lost weight into a calorie sponge. This is usually the moment when you are so happy with your results that you assume you can lower your guard and return to your old habits. This is the most frequent and natural cause for those pounds quickly piling back on again.
So, after you have carefully followed a diet and attained your desired weight, this is the time to be most careful. It is called the rebound period; like a ball that has just touched the ground, weight has a tendency to bounce back.