In a paper published this week in the JAMA journal Archives of Internal Medicine, scientists suggested that popular low-carb diets with meat protein, which are often promoted for weight loss, may contain high levels or saturated fat and cholesterol, which could lead to the “potential for adverse effects”.
"This lack of a benefit for LDL-C control is a major disadvantage in using this dietary strategy in those already at increased risk of coronary heart disease," write David Jenkins, M.D., of St. Michael's Hospital and the University of Toronto, Ontario, Canada, and colleagues.
"A plant-based low-carbohydrate diet high in vegetable proteins and oils may be an effective option in treating those with dyslipidemia for whom both weight loss and lower LDL-C concentrations are treatment goals," wrote the authors, adding that more research was needed to confirm the benefits.
Their study, which was supported by the soy protein manufacturer Solae, found that overweight individuals who ate a low-calorie, low-carbohydrate diet high in plant-based proteins for four weeks lost weight and experienced improvements in blood cholesterol levels and other heart disease risk factors.
The researchers randomly assigned 25 participants to this diet, which they term the ‘Eco-Atkins’ diet, for a period of four weeks. The vegetable proteins in this diet were derived from gluten, soy, nuts, fruits, vegetables, cereals and vegetable oils.
Another 25 participants were given a high-carbohydrate, lacto-ovo vegetarian control diet, which was based on low-fat dairy and whole grain products. The diets provided 60 per cent of participants’ estimated calorie requirements.
After four weeks, both groups recorded similar levels of weight loss – around 4kg or 8.8lbs. However, reductions in LDL-C levels and improvements in the ratios between total cholesterol and HDL-C were greater for the low-carbohydrate diet compared with the high-carbohydrate diet, wrote the researchers.
“The low-carbohydrate diet also appeared to produce beneficial changes in levels and ratios of apolipoproteins, proteins that bind to fats. In addition, small but significantly greater reductions were seen in both systolic (top number) and diastolic (bottom number) blood pressure for the low-carbohydrate vs. the high-carbohydrate group.”
The authors said their study provides insight into “debatably more effective and possibly safer tactics” for designing higher-protein diets for weight loss and cardiovascular risk reduction.
“However, it is premature to recommend the 'Eco-Atkins' diet as a weight loss diet of choice without confirmation of its efficacy in larger studies of more diverse and higher-risk individuals. Long-term studies are also essential to ascertain both sustainability and safety," they concluded.
Source:The Effect of a Plant-Based Low-Carbohydrate ('Eco-Atkins') Diet on Body Weight and Blood Lipid Concentrations in Hyperlipidemic SubjectsArchives of Internal Medicine, 2009;169 (11): 1046 DOI: 10.1001/archinternmed.2009.115Authors: David J. A. Jenkins; Julia M. W. Wong; Cyril W. C. Kendall; Amin Esfahani; Vivian W. Y. Ng; Tracy C. K. Leong; Dorothea A. Faulkner; Ed Vidgen; Kathryn A. Greaves; Gregory Paul; William Singer.