To the Editor: In a study comparing 4 popular weight-loss diets, Dr Gardner and colleagues1 concluded that the Atkins diet (very low in carbohydrates) yielded greater weight loss than the Ornish diet (very high in carbohydrates).1 Differences in carbohydrate quality between these diets and intervention fidelity suggest a different conclusion. We believe that the study is not a fair test of these diets because poor adherence to the Atkins and Ornish diet stipulations at the outset were evident.
Participants assigned to the Atkins group consumed greater amounts of high-quality carbohydrates than stipulated, as reflected by their dietary fiber intake. The Atkins diet limits fiber intake2 for the first 2 months to no more than 2 g/d; instead, it was 11 g in the study. Atkins stipulates 8 g/d during active weight loss2 ; instead, it was 15.2 g at 12-month follow-up. The Ornish diet requires 38 g/d of fiber intake,2 but participants reported only 22.1 g at 2-month follow-up despite deriving 63.1% of calories from carbohydrates; they reported only 19.3 g/d of fiber intake at 12-month follow-up. Thus, the actual intervention effects were primarily a contrast in carbohydrate quality, not a contrast in carbohydrate restriction vs fat restriction.
The significant weight-loss differences and associated secondary outcomes at 6 months therefore suggest that the modified Atkins diet in the study may have been more satiating because it had proportionately higher levels of water and fiber in its carbohydrate sources and more overall protein than the modified Ornish diet.3 The nearly 400 daily kilocalories of refined carbohydrates in the modified Ornish diet can explain the higher serum triglycerides and higher sodium intake observed for this condition.4
These findings support a conclusion that US adults should choose minimally processed carbohydrate sources that remain high in water and fiber content and low in sodium, as found in minimally processed fruits and vegetables and cooked legumes. This more parsimonious explanation is consistent with the favorable metabolic and blood pressure profiles observed with the DASH diet and the Mediterranean diet.5
Financial Disclosures: Dr McCarthy reports receiving consulting fees from the Pritikin Longevity Center, Aventura, Florida. Dr Kuo reports no conflicts of interest.
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
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