(08-07-09) Long-term effects of a very-low-carbohydrate weight loss diet compared with an isocaloric low-fat diet after 12 mo1,2,3,4

Grant D Brinkworth, Manny Noakes, Jonathan D Buckley, Jennifer B Keogh and Peter M Clifton
1 From the Preventative Health National Research Flagship, Commonwealth Scientific and Industrial Research Organization?Human Nutrition, Adelaide, Australia (GDB, MN, JBK, and PMC), and the Australian Technology Network, Centre for Metabolic Fitness and Nutritional Physiology Research Centre, University of South Australia, Adelaide, Australia (JDB).
2 None of the funding agencies played a role in the conception, design or conduct of the study, collection, management, analysis and interpretation of the data; or preparation, review, and approval of the manuscript.
3 Supported by project grants from the National Heart Foundation of Australia and the National Health and Medical Research Council of Australia. Simplot (Australia), Mt Buffalo Hazelnuts (Victoria), Webster Walnuts (Victoria), Stahmann Farms (Queensland), and Scalzo Food Industries (Victoria) donated the food used in this study.
4 Address correspondence to GD Brinkworth, Commonwealth Scientific and Industrial Research Organisation?Human Nutrition, PO Box 10041 BC, Adelaide, South Australia 5000. E-mail: [email protected] .
Background: Long-term weight loss and cardiometabolic effects of a very-low-carbohydrate, high-saturated-fat diet (LC) and a high-carbohydrate, low-fat diet (LF) have not been evaluated under isocaloric conditions.
Objective: The objective was to compare an energy-controlled LC diet with an LF diet at 1 y.
Design: Men and women (n = 118) with abdominal obesity and at least one additional metabolic syndrome risk factor were randomly assigned to either an energy-restricted ( 6?7 MJ) LC diet (4%, 35%, and 61% of energy as carbohydrate, protein, and fat, respectively) or an isocaloric LF diet (46%, 24%, and 30% of energy as carbohydrate, protein, and fat, respectively) for 1 y. Weight, body composition, and cardiometabolic risk markers were assessed.
Results: Sixty-nine participants (59%) completed the trial: 33 in the LC group and 36 in the LF group. Both groups lost similar amounts of weight (LC: ?14.5 ? 1.7 kg; LF: ?11.5 ? 1.2 kg; P = 0.14, time x diet) and body fat (LC: ?11.3 ? 1.5 kg; LF: ?9.4 ? 1.2 kg; P = 0.30). Blood pressure, fasting glucose, insulin, insulin resistance, and C-reactive protein decreased independently of diet composition. Compared with the LF group, the LC group had greater decreases in triglycerides (?0.36 ? 0.15 mmol/L; 95% CI: ?0.67, ?0.05 mmol/L; P = 0.011), increases in HDL cholesterol (0.23 ? 0.09 mmol/L; 95% CI: 0.06, 0.40 mmol/L; P = 0.018) and LDL cholesterol (0.6 ? 0.2 mmol/L; 95% CI: 0.2, 1.0 mmol/L; P = 0.001), and a greater but nonsignificant increase in apolipoprotein B (0.08 ? 0.04 g/L; 95% CI: ?0.004, 0.171 g/L; P = 0.17).
Conclusions: Under planned isoenergetic conditions, as expected, both dietary patterns resulted in similar weight loss and changes in body composition. The LC diet may offer clinical benefits to obese persons with insulin resistance. However, the increase in LDL cholesterol with the LC diet suggests that this measure should be monitored. This trial was registered with the Australian New Zealand Clinical

Source: Am J Clin Nutr 90: 23-32, 2009

News

---

In evidenza

"L'informazione presente nel sito serve a migliorare, e non a sostituire, il rapporto medico-paziente."

Per coloro che hanno problemi di salute si consiglia di consultare sempre il proprio medico curante.