Human body energy stores and losing weight

Many dieters think of stored energy as just body fat, and that to lose weight they need to follow a diet to enable the body to use up these fat stores. But there is more to losing body fat stores than just dieting, there are other stores of energy which can limit or interfere with the process of fat burning.

There are other stores of energy within the body; glycogen (carbohydrates) and protein (muscle). How the body uses these stores for energy production can change the way the body uses fat. This article discusses the stores of each energy component within the body and how they can affect weight loss.

Carbohydrates stored in the body
Glycogen is basically carbohydrates stored in the body. It is stored mainly in the muscles and to a smaller degree in the liver. Glycogen is a large storage molecule made up of millions of glucose (sugar) units. The process of storing carbohydrates causes it to hold about three times its own weight of water. The body can store a maximum of around 500 grams of glycogen but the exact amount of storage at any given time will depend largely on the nutritional status of the individual. Even if glycogen stores are full there will only be the energy equivalent to approximately 2000 calories, in other words if you didn’t eat for a whole day then most of these stores could be used up.

But how does this all relate to losing weight?
Storage of sugar (glycogen) causes the body to hold three times its weight in water. This means that if your muscles have 500 grams of glycogen storage then you’ll also be holding an extra 1500 grams of water, so a total weight of two kilograms (4.4 pounds). If you used up 90% of the glycogen stored in the muscles – which is quite likely if you cut food intake dramatically or was following a low-carbohydrate diet – then you’ll lose just less than 4 pounds in weight. This is what tends to happen when following a very low calorie diet and especially a low-carbohydrate diet, all the weight loss comes from fluid loss through reduced glycogen stores. It’s the reason why dieters lose so much weight within the first few days, and also the reason why so many dieters regain the weight after the diet ceases, the fluid is simply replaced as glycogen stores are replenished. The fact is that most of the weight lost was NOT fat loss in the first place. Knowing this information helps many people make sense of the fact that slow steady weight loss (around 1-2 pounds each week) is the best policy for permanent weight control.

Protein storage in the body
Protein in the body is used as a building material so it is not really stored in the same way as fat and carbohydrates, but because muscle is frequently broken down and used as energy the whole muscular system represents a huge potential store of energy. Some protein is always used to supply energy. It averages about 5% of total energy expenditure; this can increase to 15% during long periods of intense physical work, or high intensity exercise. Protein usage also increases when glycogen stores are low, protein is converted to glucose in the liver, thereby helping to maintain blood glucose levels. As glycogen stores are generally lowered when dieting or following a low-carbohydrate diet, it follows that more protein will be utilized for energy.

But how does this all relate to losing weight?
As is the case for glycogen, protein also holds water, about four times its weight. Thus if your body uses more protein for energy there will be a corresponding loss of fluid causing the dieter to believe a diet is working well. A loss of glycogen fluid along with protein fluid can result in some dieters losing between ten and thirty pounds in weight fairly quickly. It is inevitable that any reduction in energy intake will cause reduced protein but you should try to limit this loss as much as possible with regular exercise and an intake of high-quality protein food sources.

Fat storage in the body
Fat is stored in virtually every area of the body, not only under the skin but also inside the body cavity surrounding the organs and within muscles. We cannot determine where fat is stored or which area we burn it from first, although what we can do is reduce the amount of stored body fat we carry.

But how does this all relate to losing weight?
Fat is really the type of fuel we want to burn off in order to lose weight, so anything that helps burn more fat would be great for dieters.

One tactic is to reduce total calorie intake by only 15%. Research has shown that reducing energy intake too much causes the body to burn more protein from muscles in order to supply energy and/or essential amino acids (not enough essential amino acid intake simply because food intake too low). Cutting calories on a gradual but steady basis helps limit a decrease in metabolism and ensures you are still eating enough food to provide the body with essential proteins, vitamins and minerals for good health.

Another tactic is to exercise for longer duration at a lower intensity. Fat requires oxygen to burn completely, but oxygen can only be delivered to the working muscle cells at a steady rate, a lower rate of delivery for less fit individuals. So in order to maintain a constant fat burning state during exercise is to work at a rate which is easy to moderate in effort. A good guide to make sure you are in fat burning mode is to be able to just about hold a conversation while exercising.

A diet composed of around 60% carbohydrates, 25% protein and 15% fats of total calories can help. Remember fat is a concentrated source of energy, the less fat you eat, the more food you can consume without going over the reduced calorie intake.

Try to maintain or even better, increase lean muscle tissue. A higher degree of lean mass will help you burn more energy by increasing the basal metabolic rate. A higher metabolic rate will boost energy and fat burning.

Ensure you are obtaining the RDA for all vitamins and minerals. Many vitamins are involved in the release of energy from food, so an adequate supply gives us that vigorous feeling to want to participate in exercise and activities which in turn helps us burn more fat calories.