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Unformatted text preview: Module 2 --- Article 2 TREATMENT HIGHLIGHTS WEIGHT CONTROL Findings suggest that Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets. This 2-year study compared the effectiveness and safety of 3 nutritional protocols to achieve weight loss. The study followed 322 adults (86% of whom were men) with an average age of 52. To participate in the study, individuals needed to either (1) be between the ages of 40 and 65 years and overweight or obese, or (2) have diabetes or coronary heart disease, in which case the age and BMI1 restrictions did not apply. Participants had, on average, a BMI of 31 (moderately obese range). The participants were randomly assigned to follow 1 of 3 diets: (1) Mediterranean, restricted-calorie; (2) low-carbohydrate, nonrestricted-calorie; (3) low-fat, restricted-calorie. All participants met in small groups with dieticians for 90-minute sessions in weeks 1, 3, 5, 7, and then every 6 weeks thereafter. Participants who were having difficulty adhering to the diets received motivational telephone calls from a dietician (up to 6 times during the 2-year intervention). In some cases, spouses were instructed on how they could be more supportive. The study was based at a single work site and included the use of online questionnaires to assess dietary adherence and physical activity. The questionnaires were completed at the start of the study and at 6, 12, and 24 months. Participants were weighed monthly and underwent physical exams periodically throughout the study period. Unless otherwise noted, the findings include data from all 322 participants, with the most recent measurements used for those who did not complete the study. Among all participants who started the study, the average weight loss after 2 years was greater for the Mediterranean diet group (9.7 lbs) and the low-carbohydrate diet group (10.4 lbs) than for the low-fat diet group (6.4 lbs).2 Most of the weight loss occurred during the first 6 months. Among the 45 women, the average weight loss after 2 years was 13.7 lbs (Mediterranean diet), 5.3 lbs (low-carbohydrate diet), and 0.2 lbs (low-fat diet). Among the 277 men, the average weight loss was 8.8 lbs (Mediterranean diet), 10.8 lbs (low-carbohydrate diet), and 7.5 lbs (low-fat diet). Considering only the 272 participants who completed the study, the average weight loss was 10.1 lbs (Mediterranean diet), 12.1 lbs (low-carbohydrate diet), and 7.3 lbs (low-fat diet). Adherence to the diets during the 24 months was 90.4% (low-fat diet), 85.3% (Mediterranean diet), and 78.0% (low-carbohydrate diet). The low-carbohydrate diet was associated with more favorable changes in cholesterol levels than was the low-fat diet. Specifically, the total cholesterol to high-density lipoprotein (HDL) cholesterol ratio decreased by 20% in the lowcarbohydrate diet group, compared to 12% in the low-fat diet group. Also found were greater decreases in triglyceride levels in the low-carbohydrate diet group (23.7 mg per deciliter decrease) and in the Mediterranean diet group (21.8 mg per deciliter decrease) than in the low-fat diet group (2.7 mg per deciliter decrease). Among the 36 participants with diabetes, the Mediterranean diet was associated with more favorable changes in fasting plasma glucose levels and insulin resistance than was the low-fat diet. The authors comment that the consumption of monounsaturated fats in the Mediterranean diet may improve insulin sensitivity leading to improved glucose and insulin levels. Noting that the decreased caloric intake was similar among the 3 diet groups, the authors suggest that “a lowcarbohydrate, non-restricted-calorie diet may be optimal for those who will not follow a restricted-calorie dietary regimen.” The authors conclude that “Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets. The more favorable effects on lipids (with the low-carbohydrate diet) and on glycemic control (with the Mediterranean diet) suggest that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions.”
1 Except for individuals with diabetes or coronary heart disease, a BMI of at least 27 was required. BMI = [weight in kilograms] divided by [height in meters, squared]. To calculate BMI using pounds for weight and inches for height, go to http://www.nhlbisupport.com/bmi. All results reported here comparing the 3 diet groups describe statistically significant findings. However, when pairwise analyses were not available, data from all 3 groups were presented here without a statement regarding which pairs of outcomes entailed differences. 2 Shai I, Schwarzfuchs D, Henkin Y, et al (for the Dietary Intervention Randomized Controlled Trial [DIRECT] Group). Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. New England Journal of Medicine, 359:229-241, 2008. Support: Nuclear Research Center Negev (NRCN), the Dr. Robert C. and Veronica Atkins Research Foundation; S Daniel Abraham International Center for Health and Nutrition (Ben-Gurion University, Israel). © Copyright 2011 MWK Publishing LLC; from The Complete Practitioner: Mental Health Applications (Vol. 11, No. 8 -- August 2008) For next article, go to next page. ...
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This note was uploaded on 02/10/2011 for the course PCO 4930 taught by Professor Neimeyer during the Spring '09 term at University of Florida.
- Spring '09