Calories In Vs. Calories Out Does Not Equal Weight Loss

Dieting is usually seen as a less-than-pleasurable experience. You grit your teeth, eat as little as possible and try to ignore the hunger pangs and the rumbling belly. So when miracle diets come along promising you weight loss without the suffering, promising you that you can eat what you like, it's natural for you to be suspicious as to whether this is backed up by science.

History

The generally accepted theory is that to lose weight, you need to burn more calories than you consume through food. This is the theory put forward by the National Institute of Health's Weight-control Information Network, which emphasizes the balance between calories consumed versus calories burned. Burn more than you eat and you lose weight, while consuming more than you burn will cause you to gain weight.

Exercise

Exercise increases the amount of calories you expend during the day. However, according to studies by the Mayo Clinic, the actual role of exercise in weight loss is minimal compared to the role played by diet. Although exercise can affect your weight loss, you need to exercise significantly more than the 150 minutes of moderate exercise recommended by the National Institutes of Health. Exercise is still important in maintaining health, however, and ensuring that you lose fat rather than muscle.

Low-Calorie Diets

Traditional low-calorie diets work on restricting the calories you consume in your diet so that your calorie intake falls below the amount of calories burned throughout your day. According to nutritionist Ian Marber, this can effect your insulin levels, which help convert food into energy, so you may suffer loss of energy and extreme hunger that can test your resolve to remain on your diet. It can also cause your body to restrict its metabolism to protect its energy stores, actually preventing you from losing weight.

Ketogenic Diets

Low-carb diets are the new craze, replacing the traditional low-calorie diets. Diets such as Atkins or the Zone diet rely on ketosis to promote weight loss. By restricting the body's carbohydrate intake rather than the calorie intake, the body must burn fat rather than carbohydrates as usual for energy. This process is known as ketosis and has been shown to be effective in metabolizing body fat with less pronounced feelings of hunger associated with traditional diets.

Formula

The traditional method of measuring weight loss through caloric balance is still valid, although other factors can affect the formula. More accurate formulas exist, such as the Mifflin-St Jeor formula that can be used to calculate your caloric needs for weight maintenance and loss. According to the formula, the average person will need to burn hundreds more calories than they consume, otherwise weight loss will not occur.