Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women

Manny Noakes, Jennifer B. Keogh, Paul R. Foster, Peter M. Clifton

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348 Citations (Scopus)


Background: Limited evidence suggests that a higher ratio of protein to carbohydrate during weight loss has metabolic advantages. Objective: The objective was to evaluate the effects of a diet with a high ratio of protein to carbohydrate during weight loss on body composition, cardiovascular disease risk, nutritional status, and markers of bone turnover and renal function in overweight women. Design: The subjects were randomly assigned to 1 of 2 isocaloric 5600-kJ dietary interventions for 12 wk according to a parallel design: a high-protein (HP) or a high-carbohydrate (HC) diet. Results: One hundred women with a mean (±SD) body mass index (in kg/m2) of 32 ± 6 and age of 49 ± 9 y completed the study. Weight loss was 7.3 ± 0.3 kg with both diets. Subjects with high serum triacylglycerol (>1.5 mmol/L) lost more fat mass with the HP than with the HC diet (x̄ ± SEM: 6.4 ± 0.7 and 3.4 ± 0.7 kg, respectively; P = 0.035) and had a greater decrease in triacylglycerol concentrations with the HP (-0.59 ± 0.19 mmol/L) than with the HC (-0.03 ± 0.04 mmol/L) diet (P = 0.023 for diet × triacylglycerol interaction). Triacylglycerol concentrations decreased more with the HP (0.30 ± 0.10 mmol/L) than with the HC (0.10 ± 0.06 mmol/L) diet (P = 0.007). Fasting LDL-cholesterol, HDL-cholesterol, glucose, insulin, free fatty acid, and C-reactive protein concentrations decreased with weight loss. Serum vitamin B-12 increased 9% with the HP diet and decreased 13% with the HC diet (P < 0.0001 between diets). Folate and vitamin B-6 increased with both diets; homocysteine did not change significantly. Bone turnover markers increased 8-12% and calcium excretion decreased by 0.8 mmol/d (P < 0.01). Creatinine clearance decreased from 82 ± 3.3 to 75 ± 3.0 mL/min (P = 0.002). Conclusion: An energy-restricted, high-protein, low-fat diet provides nutritional and metabolic benefits that are equal to and sometimes greater than those observed with a high-carbohydrate diet.

Original languageEnglish
Pages (from-to)1298-1306
Number of pages9
JournalAmerican Journal of Clinical Nutrition
Issue number6
Publication statusPublished or Issued - 2005
Externally publishedYes


  • Bone turnover
  • Diet composition
  • Dual-energy X-ray absorptiometry
  • High-protein diet
  • Lipids
  • Nutritional status
  • Weight loss

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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