In a small clinical trial of obese adults, researchers found that those assigned to follow a low-carbohydrate diet lost more weight over a year than those who followed a low-fat plan. They also had bigger improvements in their cholesterol and triglyceride levels.
Yet in this study, people on the low-carb diet saw slightly greater improvements in their levels of good HDL cholesterol and triglycerides – another type of blood fat. That could have been due to the bigger weight loss, or to the greater amounts of good unsaturated fat in their diets.
For one, people on the low-carbohydrate diet didn’t stick to it all that well. The regimen called for no more than 40 grams of carbohydrates a day – the equivalent of about two slices of bread. But, by the end of the year, people in the low-carbohydrate group were averaging 127 grams of carbohydrates a day.
But one of the concerns with a low-carbohydrate diet is that people will not get enough fiber. A high-fiber diet can help ward off heart disease, and studies suggest it can aid weight loss by making people feel more full.
The current study included 148 adults who were obese but free of diabetes and heart problems. About half were randomly assigned to a low-carbohydrate diet, while the rest were placed on a low-fat plan.
People in both groups had counseling sessions with a dietitian: The low-fat group was told to get no more than 30 percent of their daily calories from fat, while the low-carbohydrate group was given a limit of 40 grams of carbohydrates per day. At the end of one year, the low-fat group averaged nearly 200 grams of carbohydrate daily compared to about 130 for the low-carb group, according to the study.
In the end, 82 percent of the low-fat group stuck with the diet for a full year. The same was true for 79 percent of the low-carbohydrate group. By the one-year mark, people in the low-carbohydrate group had lost an average of almost 12 pounds. That compared with only four pounds for the low-fat group.
Prior to this, it was then agreed that there is no one-size-fits-all diet. When it comes to heart health, for example, there is strong evidence that diet high in good carbohydrates is a smart option.
Ultimately, people need to make diet changes they can keep up for the long haul – not just until they lose a certain amount of weight. This is because the weight may come back if you go back to your old ways.