Low-Carbohydrate Diets

The term “low-carbohydrate diet” is loosely applied to both the diets that significantly restrict carbohydrates to less than 20% of caloric intake and to the diets that merely limit the carbohydrate intake to less than the recommended amounts (typically less than 45% of caloric intake).

Although it is difficult to estimate the number of individuals following a low-carbohydrate regimen (carbohydrates between <10% to 30% of daily energy intake), the popularity and number of low-carbohydrate diets reflect a high level of interest. Certain dietary plans such as the Atkins diet minimize total carbohydrate consumption without fat and energy restriction while many reduce carbohydrate intake and alter macronutrient composition (i.e. Sugar Busters and Zone diets). Other regimens like the South Beach diet combine various strategies across different phases to modulate carbohydrate consumption. The long-standing rationale underlying carbohydrate restriction is that reduced carbohydrate intake and the resulting ketosis (i.e. obtainment of energy from adipose tissue) will decrease basal insulin levels thereby promoting lipolysis and reducing lipogenesis, eventually leading to the fat loss.

Multiple Benefits Of Low-Carb Diets Are Well Documented

Weight loss while following a low-carbohydrate diet is thought to result from a combination of factors: the satiating effect of protein, increased energy expenditure, appetite suppression from ketosis, increased bound-water loss and food choice restriction. A growing body of evidence indicates that low-carbohydrate diets might be more effective for short-term weight loss than low-fat diets, while longer-term studies show that differences between the two regimes dissipate after 1 year.

The particular characteristics of a low-carbohydrate diet are associated with both favorable and unfavorable effects on the body that go beyond possible weight loss.  The most dramatic and consistent lipid response to a low-carb diet is a moderate to large decrease in fasting triglyceride levels and postprandial triglyceride responses to a fat-rich meal. For example, the researchers who conducted the clinical trial reported that triglyceride levels had decreased by 28.1% in a population following a low-carbohydrate diet.

Moreover, in this clinical trial the treatment with this type of diet was associated with an improvement in insulin sensitivity, in the sense that progressively less insulin was secreted to maintain the same blood glucose concentrations.

Long-Term risks Of Low-Carb Diets

Nevertheless, these results should not be interpreted as precluding the possibility of harm from low-carbohydrate diets through changes of serum lipid profile. In one study, increases in low-density lipoprotein cholesterol levels of more than 10% were seen in 30% of subjects in the low-carbohydrate diet group and only 16% in the low-calorie diet group, and 2 participants in the low-carb diet group were withdrawn from the trial because of important adverse effects on blood lipid levels. Furthermore, people on low-carb diets consume a large amount of saturated fats, representing 17% of total energy intake, which is almost double the current recommendation of health organizations. Saturated fats are associated with increased levels of LDL cholesterol, a well-known risk factor for coronary artery disease. Although the beneficial effects of low-carbohydrate diets on serum lipid levels may offset the negative effect of increased levels of saturated fat in the short term, the impact of the diet on low-density lipoprotein cholesterol levels over the long term (2–5 years) must be evaluated.

Finally, two other studies produced evidences that low-carb diets are typically nutritionally poor, with low amounts of vitamins A, B6 and E and of folate, calcium, magnesium, iron, potassium and dietary fiber. This is because, overall, low-carbohydrate diets are usually low in fruits and vegetables, dairy products and whole grains. These dietary patterns, if maintained over long periods of time, increase the risk of a variety of chronic diseases, including hypertension and cancer. High-protein diets affect renal function and can place greater demands on the kidney and liver for metabolizing and excreting excess urea and ammonia. They may be a health hazard for patients with renal or liver impaired functions in general, particularly patients who are also diabetic.

See Also: The facts about Atkins Diet: Pros and Cons

Eventually, the success in losing weight depends on the adherence to the proper eating plan. Long-term sustainable weight loss, however, is hardly ever achieved without serious lifestyle modifications. Sedentary lifestyle is one of the major reasons people become fat, and dieting alone is unlikely to be successful without incorporating physical activities in everyday life. This is something to keep in mind regardless of what type of diet you chose.