High-fat Low-carb Diets Could Mean Significant Heart Risk

Main Category: Nutrition / Diet
Also Included In: Heart Disease;  Cardiovascular / Cardiology;  Diabetes
Article Date: 09 Dec 2009 - 0:00 PST

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New scientific research has shown that low-carbohydrate high-fat diets, made popular by the likes of the Atkins diet, do not achieve more weight loss than low-fat high-carbohydrate diets. Worryingly, the research, lead by Dr Steven Hunter from the Royal Victoria Hospital, Belfast, also shows significantly increased risks of cardiovascular disease for people following low-carbohydrate high-fat diets.

The research shows that the risks of low-carbohydrate high-fat diets far outweigh the potential benefits gained by overweight and obese people through weight loss, including improvements in blood pressure and risk factors for coronary heart disease.

The research results, released hot on the heels of both National Obesity Week and World Diabetes Day, are particularly important for nearly a quarter (24%^¹) of the UK adult population, and 16% of the child population, now classified as obese and at risk of Type 2 Diabetes - 80%^² of all people diagnosed with Type 2 diabetes are overweight. Type 2 Diabetes is the result of inadequate insulin production and/or insulin resistance, which means that the right levels of glucose (our main source of energy from food) are not maintained naturally by the body. There are 180 million people in the world with diabetes and the World Health Organisation predicts this number will double in the next 20 years.

Dr Hunter, Royal Victoria Hospital, Belfast, said: "The worldwide obesity pandemic is a major public health concern and strongly linked to rises in diabetes and cardiovascular disease. By advocating low-carbohydrate high-fat diets as a weapon against obesity and diabetes, health professionals could be contributing to a dangerous rise in cardiovascular disease".

The research study, conducted among a group of obese pre-diabetic adults, compared the results of following a low-fat high-carbohydrate diet (20% fat, 60% carbohydrate) with a high-fat low-carbohydrate diet (60% fat, 20% carbohydrate). It showed that in all areas, other than the risk of cardiovascular disease, the diets have equal health benefits. The same amount of weight is lost; there is no significant difference in the body's glucose uptake or production; and meal tolerance-related insulin secretion is comparable. However, the study revealed a significant difference in overall systemic arterial stiffness and pointed to increased cardiovascular risk factors from high-fat low-carbohydrate diets.

Dr Hunter continued: "High-fat diets have become popular because they seemingly promote more rapid weight loss and because of their palatability. However, we now have proof that they do not help people lose weight any faster than more conventional diets, and the potential negatives of increased cardiovascular risks far outweigh the potential positives of more easily sustained dieting/weight loss, especially when there is a proven and safe alternative in low-fat high-carbohydrate weight loss diets."

According to Dr Hunter, the challenge now is to find ways to make low-fat high-carbohydrate diets more palatable and easier to maintain, so that a long-term positive outcome is achieved.

The Food Standards Agency says that saturated fat should account for less than 11% of the total diet for a normal person, and Dr Hunter concludes: "If your New Year's resolution is to lose weight, make sure you do it the right way and don't burden your body with additional unnecessary health risks by falling for the lure of the seemingly easy and fast weight loss offered by high-fat diets. The best approach for your overall health is a low-fat high-carbohydrate diet, coupled with exercise."

^¹ NHS Statistics on obesity, physical activity and diet: England, January 2008, published 31 January 2008

^² Diabetes UK

Reference

Bradley U et al.
"Low-fat versus low-carbohydrate weight reduction diets: effects on weight loss, insulin resistance and cardiovascular risk. A randomised trial."
Diabetes. December 2009, vol.58, no. 12, 2741-2748. doi: 10.2337/db09-0098

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