Low-carb diets help many people lose weight, but are they safe? New research shows that short-term use of a low-carb diet does not cause vascular problems.
Many people are viewing carbohydrates rather than fats or calories as the key to weight loss. Critics, however, argue that consuming fewer carbohydrates means consuming more fat, and that, in turn, may increase cardiovascular risk. Recent research carried out at Johns Hopkins University shows that, at least over the course of months, a low-carb diet does not cause cardiovascular problems.
“The take-home message is that a low-carb diet may be a good option for people, and there appears to be no effect on vascular health, at least in the short term,” says exercise physiologist Kerry Stewart, lead author of the study.
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Are low-carb, “high fat” diets effective and safe?
Stewart and his colleagues tracked 46 men and women aged 30 to 65 who weighed an average of 218 pounds before the study. The participants consumed the same number of calories per day, but half followed a low-carbohydrate diet while the others followed a low-fat diet. Everyone participated in supervised aerobics and resistance training exercises three times per week.
The researchers assessed the condition of each participant’s arteries at the start of the study and after he or she had lost ten pounds. They used two measures of vascular health, both involving the responses of blood vessels in the finger, plus blood pressure and heart rate.
They found that the low-carb dieters reached the goal of ten pounds of weight loss fifty percent faster than those eating less fat. The low-carb dieters took an average of 45 days to lose ten pounds while the low-fat group took 70 days.
The other key finding of the study, presented at the 58th Annual Meeting of the American College of Sports Medicine, was that neither the low-carbohydrate nor the low-fat diet caused any negative cardiovascular changes. The two diets were equal on all the cardiovascular measurements.
“Our study should help allay the concerns that many people who need to lose weight have about choosing a low-carb diet instead of a low-fat one, and provide re-assurance that both types of diet are effective at weight loss and that a low-carb approach does not seem to pose any immediate risk to vascular health,” says Stewart.
A surprising finding
Stewart was intrigued to find that participants on the low-carbohydrate diet actually ended up eating less rather than more fat. While fat made up a higher percentage of their food intake, they actually consumed less fat (but more protein) than before the study.
“When you look at the absolute amount of fat being consumed, the low-carb group is actually conuming fewer grams of fat than before starting the diet,” says Stewart. “So when the headlines read ‘people on a high-fat diet’, that is not entirely accurate. They are actually consuming less fat and are overall eating healthier.”
His conclusion: “More people should be considering a low-carb diet as a good option.”
