Trimming carbohydrate intake results in healthy improvements in blood fat levels, even if a person doesn’t lose an ounce, a new study shows.
“These dietary fads tend to come and go,” Dr. Ronald M. Krauss of Children’s Hospital Oakland Research Institute in Oakland, California, told Reuters Health. “In the case of low carbohydrates, people shouldn’t be so quick to throw that away and move on to the next diet. Limiting carbohydrates can be beneficial even if people aren’t successful at losing weight.”
Scientists now believe that carbohydrates, especially simple sugars, can cause unhealthy changes in blood fats by causing fat to collect in the liver - just as it does on one’s thighs or belly. These fats eventually find their way into the bloodstream, Krauss explained.
Cutting down on these fat deposits by cutting carbs reduces fat levels in the blood, and may also boost the body’s ability to break down fats that do reach the bloodstream.
To investigate whether moderate reduction in carbohydrate intake might affect cholesterol levels, Krauss and his team had a group of 178 overweight men eat a standard diet including 54 percent energy intake from carbohydrates for one week.
The men were then randomly assigned to continue the same diet, or switch to a 39 percent carbohydrate diet, or a 26 percent carb diet for three weeks.
For an additional five weeks, men ate a similar diet but their calorie intakes were reduced to produce weight loss. In the final four weeks of the study, their energy intake was adjusted for weight stabilization.
Compared to the men who stayed on the standard diet, those with the lowest carb intake showed reductions in harmful triglycerides and “bad” LDL cholesterol levels. They also enjoyed an increase in the ratio of “good” HDL cholesterol to total cholesterol levels, and other improvements in their blood fat profile.
These healthy changes were seen whether or not the men were eating less saturated fat, and whether or not they lost weight.
The 54 percent carbohydrate diet resembles the normal diet many of us consume by following standard dietary recommendations, Krauss said. People can cut their carbohydrate intake to a level similar to that used in the study by “avoiding the kinds of food we don’t need in our diet anyway-sugary foods, white rice, pasta, white bread,” he added.
“This type of diet really needs to be done in consultation with a dietitian to get the balance that we used,” Krauss emphasized. But such a diet, he noted, is much less restrictive than, for example, the Atkins’ approach, and would relatively simple to follow.
SOURCE: American Journal of Clinical Nutrition, May 2006.
Revision date: June 20, 2011
Last revised: by Sebastian Scheller, MD, ScD