It is true that some of the glucose ingested can be converted to fatty acids by the liver when there is an excess of energy available to the body. But eating a diet low in carbohydrates is not a good solution to a weight problem either. For example, many weight loss programs suggest diets that are high in protein and low in carbohydrates. Besides high levels of ammonia in the body through the breakdown of protein, a low carbohydrate diet will force the body into a condition known as ketosis. Ketosis comes from the root word ketones which are produced in the liver through the incomplete breakdown of fat. Although some of the amino acids that come from the diet are gluconeogenic, meaning glucose producing, many amino acids are ketogenic and cannot enter the citric acid cycle. Therefore, the level of ketones in the body rises while levels of glucose fall and many organs begin to function less efficiently, including the brain, which relies heavily on glucose. Furthermore, fats can only be metabolized when there is a certain amount of glucose present to produce oxaloacetate that condenses with acetyl CoA in the citric acid cycle. Since fatty acids are degraded directly to acetyl CoA, they cannot be used as an energy source. Instead, they too are transformed in ketones. Although many tissues can utilize ketones for energy, high levels in the blood stream are dangerous and low amounts of glucose in the blood can be detrimental to the brain.
In addition, low carbohydrate diets without exercise will slow down metabolism. Weight loss may be realized but the type of weight that is actually lost may include muscle mass as well as fat. With less lean body mass, resting metabolic rates will decrease since skeletal muscle requires more energy at rest and during exercise than adipose tissue. In conclusion, exercising during fasting periods and eating a diet high in carbohydrates will not only increase well being, but will also help to lose weight more effectively. Monitoring the amount of carbohydrate intake with the amount of exercise will help to refine weight loss.