Fri, Jul-23-10, 02:12
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Plan: LC Maintenance
Stats: 215/147/150
BF:
Progress: 105%
Location: UK
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Popular weight loss diets have different effects on micronutrient adequacy
Quote:
From The American Journal of Clinical Nutrition Online
August 2010
Popular weight loss diets have different effects on micronutrient adequacy
Background Health professionals agree that obesity is a major public health issue, and the American public agrees, as indicated by the $30 billion spent on weight-loss products yearly. Indeed, there is no shortage of advice on how to lose weight, with a new weight-loss diet published almost daily. These books often advocate diets of various macronutrient distributions that sometimes deviate from that recommended by the US Department of Agriculture’s Dietary Guidelines for Americans (45–65%, 20–35%, and 10–35% of calories from carbohydrates, fat, and protein, respectively). Despite the intense scientific and public interest, there is much debate on whether any of the popular weight-loss diets is superior to the others. There is also concern that some may result in inadequate vitamin and mineral intake. To study this, researchers at the Stanford University Medical School compared what people tend to eat when they are asked to follow 4 common weight-loss regimens: Atkins, Zone, LEARN (Lifestyle, Exercise, Attitudes, Relationships, Nutrition), and Ornish diets. Their results are published in the August 2010 issue of The American Journal of Clinical Nutrition.
Study Design To compare the nutritional adequacy of these diets, the researchers enrolled a total of 291 overweight or obese [body mass index (in kg/m2: 27-40)], premenopausal (mean age: ~41 y) women assigned randomly to read and follow one of the diets of interest. After demonstrating a basic understanding of the diet, each participant was then asked to follow the assigned diet for 1 y. Subjects were weighed and measured throughout the study, and their dietary intakes were assessed with the use of 3 separate 24-h diet recalls.
Results The results presented here were those collected 8 wk into the study, when dietary adherence was at its best. The researchers found that, although none of the diets was adhered to in its entirety, subjects decreased their energy consumption by ~500 kcal/d regardless of diet plan. However, macronutrient intake was greatly influenced by which diet was being followed. For instance, those following the Atkins diet (known for its “low-carb” approach) were obtaining 17% of their energy from carbohydrates, compared with those women consuming the Ornish diet, who were obtaining 63% of energy from carbohydrates. Accordingly, women consuming the Atkins diet obtained relatively more of their calories from fats and protein compared with those consuming the Ornish diet. Women following the Zone plan consumed intermediate amounts of the macronutrients, amounts relatively close to those recommended by the Dietary Guidelines. Importantly, following the Atkins, LEARN, and Ornish dietary patterns resulted in increased risk of several micronutrient deficiencies; the opposite was true for the Zone-like diet, which actually improved the vitamin and mineral intakes of many participants.
Conclusions The authors concluded that “there may be a micronutrient advantage to diets providing moderately low carbohydrate amounts and that contain nutrient-dense foods.”
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http://www.ajcn.org/misc/release3.dtl#gard |
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