Have you tried to lose weight before? Have you been on a diet where you count the calories and eat tiny portions? Were you told it is all about ‘calories in – calories out’? Did you lose weight at first but then put it all back on? Everybody puts the weight back on because calorie restricted diets DO NOT WORK in the long term. There are two major biological reasons why they fail.
Metabolism and Hormones
These are two separate things but nothing happens in the body in isolation. Everything is interconnected and it is important to understand what they are both doing. The ‘calories in – calories out’ theory suggests that the body has a large container where all the calories go and if you take more calories out than you put in, the energy store will reduce and you will lose weight. The theory does not work because you don’t have one store for calories; you have two distinctly different stores of energy.
You store glucose (sugar) in the liver in a form called glycogen. You can only store a small amount of energy like this. (Usually about 2,500 calories.) When this store is full the liver turns excess sugar into fat and stores it in the fat cells all over the body. (The amount of energy you can store in our fat cells is unlimited, which is why some obese people become enormous.) Most of the energy you use each day is needed to keep you alive: it is used to maintain your temperature and power your brain, heart and all the other organs. Only a small percentage is used in exercise.
When you go on a diet, you are eating fewer calories than you need to maintain your metabolism. You replace the energy shortfall by taking it out of the glycogen store. However, the glycogen store is small and you can empty it quickly. At this point, your body has a problem; there is not enough energy to maintain all of its functions. The body is very good at looking after itself so it reduces the amount of energy it needs for regular metabolism. Temperature goes down slightly, the brain is less active and you feel cold and listless. Your body has now reduced its metabolic rate to balance the energy supply. The trouble is you don’t feel very good and you have now stopped losing weight. If you reduce your calories even more you go through the same process again and end up with an even lower metabolism. You eventually give up the diet because it is so difficult. When you go back to eating normally, you pile the weight back on because your body has a new and much lower requirement for energy.
Why doesn’t the body use the fat stores for energy as soon as the glycogen store is empty? This is where the hormones come in and the most important hormone is Insulin. Insulin has a couple of important roles to play in all of this.
When you digest the carbohydrate you eat, your blood sugar level goes up. Too much sugar in the blood is toxic so your pancreas produces the hormone Insulin. Insulin lowers the level of sugar in the blood by transporting it into all the cells that need more energy. All the extra glucose you don’t need immediately is stored as glycogen and when the glycogen store is full Insulin prompts the liver to convert the sugar into fat and store it in the fat cells. Excess sugar is turned into fat by the action of Insulin, which is all very helpful so far. However, Insulin also prevents the conversion of stored fat back into available energy. When you have high levels of Insulin in your blood you cannot access your fat stores.
Therefore, to lose weight and keep it off you do not reduce calories, instead you have to reduce your Insulin levels. Who wants to lose a Million Pounds will show you to do this.