Biochemistry of a Low-Carbohydrate Diet

For quite a while now, the popularity of low-carb diets has escalated. Most restaurants offer low-carb options and supermarket shelves contain huge numbers of low-carb products. Literally millions of people are on or have used these diets and low-carb products sales are in the billions, but most do not know how this diet works and if the science is there to show they are more effective than other diets.

Low-Carb Diets and Insulin

Low-carb diets primarily work through calorie reduction and by controlling the release of insulin into the blood stream through the limiting of carbohydrates into the diet. Glucose results from the breakdown of food and your body releases insulin as a response in the same proportion as the glucose it receives. Insulin helps the cells to absorb the glucose and use it as fuel. Insulin also causes a reduced ability of the body's fat breakdown functions, as well as promotes the creation of cholesterol in the blood, so too much creates conditions that foster weight gain and obesity.

Glucagons

Low blood sugar prompts the release of the hormone glucagons, which has been found to act the opposite of insulin. It activates fuel breakdown enzymes and prevents the release of enzymes that store energy (create fat). This is the reason behind the fat burning found in low-carb diets.

Blood Glucose

Carbs, especially simple carbs like refined sugar and flour, contain higher levels of glucose than protein of fats do. This means that the more of them you consume, the higher your blood sugar and insulin levels. Low-carb diets seek to increase the secretion of glucagons while limiting the amount of insulin released. Different diets rely on different formulas of carbs, fats and proteins to make this happen.

Ketosis

Very low-carb diets, such as Atkins diet, also attempt to force your body into a state of ketosis. Ketosis is when your body receives such a small amount of glucose from your diet that it begins to turn fat into ketones that your body then use for fuel. Excess ketones are not stored, but are released on your breath and in urine.

Scientific Studies

For a long while, the benefits of ketosis in weight loss were hotly debated. Many were contributing the superior results of low-carb diets to excess water weight or to calorie restriction, but in their landmark 2003 study, "Thermodynamics and Metabolic Advantage of Weight Loss Diets," Richard Feinman and Eugene Fine showed that ketosis does indeed play a vital part in the increased success of low-carb diets. They also showed that low-carb diets are more successful at reducing body fat than other diets, such as low-fat diets, and result in greater weight loss. This study proved that, when it comes to diets, the old adage "a calorie is a calorie" is not true, and that burning calories by following a low-carb eating plan yields better results. Other studies, like Greene, Willett, Devecis and Skaf's "Pilot 12-week feeding weight-loss comparison: Low-fat vs. low-carbohydrate (ketogenic) diets" found the same type of superior weight loss results.

References

• Wendy Pogozelski, Nicholas Arpaia, Salvatore Priore-State University of New York College at Geneseo; The metabolic effects of low-carbohydrate diets and incorporation into a biochemistry course; Biochemistry and Molecular Biology Education; 33, 2, 91-100; 2005
• Greene P, Willett W, Devecis J, A. Skaf: Pilot 12-week feeding weight-loss comparison: Low-fat vs. low-carbohydrate (ketogenic) diets; Obesity Research, 2003, 11:A23
• Richard D. Feinman, Eugene J. Fine; Thermodynamics and Metabolic Advantage of Weight Loss Diets; Metabolic Syndrome and Related Disorders. September 2003, 1(3): 209-219, 2004