There are approximately 3500 calories per pound of body fat. So in order to lose just one pound of that stored fat we need to burn off 3500 extra calories right?. Sounds quite simple but more often that not its much harder than it sounds. The fact is that the calories per pound will never add up when losing weight. In this post I will be looking at the factors that make it more than just simply 3500 calories.
If you cut your daily calorie intake by 500 less than the body requires it seems logical to assume that fat stores will supply the additional energy requirements. However energy metabolism is complex and can be different between individuals. Which fuel the body uses up to make up that calorie deficit really depends on many factors; your fitness levels, present energy stores, motivation levels, type of exercise chosen, genetic predisposition and nutritional state are a few of the important factors.
During calorie reduction some fuel from fat stores will be used as that’s the role of excess body fat. The problem is that fat is not the best source of energy for the cells. Muscle cells need a constant supply of oxygen in order to burn fat continuously. At rest enough oxygen can easily be supplied but resting hardly uses any calories at all, we may only burn 50 calories an hour. Remember we need to burn 3500 extra calories per pound of fat so we must actively move to increase the total calories burned, now this is where things can get complicated!
Exercising obviously burns many more calories but due to low fitness levels most sedentary people cannot supply enough oxygen to enable millions of working cells to continue burning fat for energy. The cells must use another fuel, preferably a quick-burning fuel that requires no oxygen – the role of carbohydrates!
The result is carbohydrates and fats are BOTH used to supply the cells energy with carbs being the predominant fuel. The proportion of carbohydrate to fat used depends on factors such as the individual fitness level and the type/intensity of exercise performed. These facts help explain the reason calculations become confusing, dieters reduce intake in calories per pound of fat without realizing that body fat cannot make up all the deficit in calories. The main point here is that we need to burn a far greater number of calories per pound of fat to burn off one pound of fat.
Low carb diets can help some people lose weight however most of the loss will not all be fat especially in the initial stages when weight loss is rapid. Remember I said cells cannot use all fat for energy because they need to be supplied with sufficient oxygen to burn it, also overweight people tend to have lower fitness levels than lean people thus their bodies cannot always keep up with oxygen demands required when exercising.
Our body has a clever mechanism for energy metabolism, if carbs are limited it simply burns more protein by converting it to carbs in the liver, a process known as Gluconeogenesis. Gluconeogenesis actually goes on all the time but if carbs are restricted the process is accelerated especially during exercise or even light activities for many overweight people. More protein lost from cells results in increased fluid loss from the body!
Remember the body always burns a combination of fats, carbohydrates and protein and there is more reliance on the latter two fuels when movements demand more effort and therefore oxygen. To burn off enough calories per pound of fat we need to take into account the number of calories that come from carbs and protein.