Low-fat Verses Low-carb Diet

Diets promoted for weight loss and better health abound, and one of the ongoing controversies focuses on which is better---a low-fat diet or a low-carb diet. Health experts say you can lose weight on either type of diet as long as you restrict calories, but will more likely keep the pounds off on a low-fat diet.

Background

Some promoters of low-fat diets, including cardiologist Dr. Dean Ornish, recommend eating very little fat---keeping it low as 10 percent of your daily caloric intake. More moderate low-fat diets, such as those promoted by the American Heart Association, restrict fat to less than 30 percent of calories. Low-fat diets emphasize complex carbohydrates such as vegetables and whole grains, with small amounts of lean meat and poultry and low-fat dairy products. Popular low-carbohydrate diets such as South Beach, the Zone and the Atkins Diet generally restrict carbohydrates to 40 percent or less of daily calories, but vary in their ratios of fat and protein. Low-carb diets greatly restrict refined carbohydrates such as sugar and white bread and (at least in the initial phases) limit natural carbs such as fruit and whole grains.

Weight Loss

In the first year, low-carb diets result in greater weight loss, according to a study published in the March 2010 issue of the "Annals of Internal Medicine." But over the long run, cutting fat works better. After three years, followers of a low-fat diet kept more weight off. And most members of the National Weight Control Registry, an ongoing study of more than 5,000 people who have lost weight and kept it off for at least three years, follow a low-calorie, low-fat diet. Cutting calories matters more than what type of calories you eat, though, reported Harvard researchers who studied diets with different ratios of carbohydrates, protein and fat, and reported the results in the Feb. 26, 2009 issue of "The New England Journal of Medicine."

Low-Fat Diets and Health

Low-fat diets include plenty of healthful foods such as vegetables, fruits and whole grains and tend to be high in fiber. If you follow a vegan diet (one with no animal foods at all), you might need to take vitamin B12, calcium and vitamin D supplements. Very low fat diets could lack essential fatty acids such as omega-3s that may promote good health. Do not put a child under the age of 2 on a low-fat diet, cautions the American Academy of Pediatrics.

Low-Carb Diets and Health

Low-carb diets can help improve blood sugar control in people with type 2 diabetes, according to a report in the December 2008 issue of "Nutrition and Metabolism." Very-low-carb diets lack fiber, and British researchers reported in the February 2007 issue of "Applied and Environmental Microbiolgy" that a very-low-carb diet inhibited the growth of bacteria in the gut that produce compounds may help ward off colorectal cancer.

The Bottom Line

If you want to lose weight, cutting calories matters more than what kind of diet you follow, although a low-fat diet may have the edge over the long run. For the healthiest diet, replace refined carbs with complex carbs (vegetables and whole grains), watch your portions, and use healthier fats such as olive oil in place of saturated fats and trans fats. You can easily fit this healthful eating style into either a low-fat or low-carb regimen.