Atkins diet is more effective and healthier than rival regimes, say medical researchers

By Jeremy Laurance Health Editor

22 May 2003

Robert Atkins, the weight-loss guru whose diet books sold in their millions, has won posthumous backing for his controversial theory about how to lose weight.

The first randomised controlled trial comparing his high-fat, low-carbohydrate diet with a conventional low-fat eating plan found people on the Atkins diet lost weight quicker and had improved levels of blood fats, with increased amounts of "good" cholesterol.

The finding will surprise the medical establishment which has long argued that the Atkins diet was potentially damaging to health and could affect kidney function and raise "bad" cholesterol levels.

Full story: independent.co.uk

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Hepatic de novo lipogenesis in normoinsulinemic and hyperinsulinemic subjects consuming high-fat, low-carbohydrate and low-fat, high-carbohydrate isoenergetic diets

"Compared with baseline, consumption of the high-fat, low-carbohydrate diet did not affect triacylglycerol concentrations. However, after the low-fat, high-carbohydrate diet, triacylglycerols increased significantly and DNL was 5–6-fold higher than in normoinsulinemic subjects consuming a high-fat diet. The increase in triacylglycerol after the low-fat, high-carbohydrate diet was correlated with fractional DNL (P < 0.01), indicating that subjects with high DNL had the greatest increase in triacylglycerols.

Conclusions: These results support the concept that both hyperinsulinemia and a low-fat diet increase DNL, and that DNL contributes to hypertriglyceridemia."

American Journal of Clinical Nutrition, Vol. 77, No. 1, 43-50, January 2003

Full article: American Journal of Clinical Nutrition

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Effect of protein and methionine intakes on plasma homocysteine

Effect of protein and methionine intakes on plasma homocysteine concentrations: a 6-mo randomized controlled trial in overweight subjects1,2,3

Nikolaj Haulrik, Søren Toubro, Jørn Dyerberg, Steen Stender, Annebeth R Skov and Arne Astrup

1 From the Research Department of Human Nutrition, The Royal Veterinary and Agricultural University, Copenhagen.

Background: A high plasma homocysteine concentration is an independent risk factor for cardiovascular disease. Homocysteine concentrations are thought to be raised by high protein and methionine intakes.

Objective: Our goal was to investigate the effects of high and low protein and methionine intakes on homocysteine in overweight subjects.

Design: Sixty-five overweight subjects were randomly assigned to a 6-mo intervention with a low-protein, low-methionine diet (LP: 12% of total energy, 1.4 g methionine/d; n = 25); a high-protein, high-methionine diet (HP: 22% of total energy, 2.7 g methionine/d; n = 25), both of which had similar fat contents (30% of total energy); or a control diet with an intermediate protein content (n = 15). All food was self-selected at a shop at the department. Protein intake was increased in the HP group mainly through lean meat and low-fat dairy products. Dietary compliance was evaluated by urinary nitrogen excretion.

Results: Homocysteine concentrations did not change significantly in the LP or control groups but were 25% lower in the HP group (NS). Homocysteine concentrations after the 3-mo intervention were inversely associated with vitamin B-12 intake and with weight change (by multivariate analysis performed for all subjects), but not with methionine or protein intake. Sixty-nine percent of the variation could be explained by baseline homocysteine (P < 0.001), 2% by vitamin B-12 (P = 0.02), and another 2% by weight change (P = 0.06). The plasma homocysteine concentration after 6 mo was associated only with baseline homocysteine (P < 0.001).

Conclusion: A high-protein, high-methionine diet does not raise homocysteine concentrations compared with a low-protein, low-methionine diet in overweight subjects.

Key Words: Protein • methionine • homocysteine • diet • obesity • cardiovascular disease

American Journal of Clinical Nutrition, Vol. 76, No. 6, 1202-1206, December 2002 © 2002 American Society for Clinical Nutrition

Source: http://www.ajcn.org/cgi/content/abstract/76/6/1202

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Effects of dietary fructose on plasma lipids

Effects of dietary fructose on plasma lipids in healthy subjects1,2,3

John P Bantle, Susan K Raatz, William Thomas and Angeliki Georgopoulos

1 From the Department of Medicine, the General Clinical Research Center, the Division of Biostatistics, and the School of Public Health, the University of Minnesota, Minneapolis, and the Veterans Administration Medical Center, Minneapolis.

Background: About 9% of average dietary energy intake in the United States comes from fructose. Such a high consumption raises concern about the metabolic effects of this sugar.

Objective: The objective of this study was to determine the effect of dietary fructose on plasma lipids.

Design: The study was conducted in the General Clinical Research Center at Fairview-University of Minnesota Medical Center. The participants were 24 healthy adult volunteers (12 men and 12 women; 6 of each sex were aged <40 y and 6 of each sex were aged 40 y). All subjects received 2 isoenergetic study diets assigned by using a randomized, balanced crossover design. One diet provided 17% of energy as fructose. The other diet was sweetened with glucose and was nearly devoid of fructose. Each diet was fed for 6 wk. Both diets were composed of common foods and contained nearly identical amounts of carbohydrate, protein, fat, fiber, cholesterol, and saturated, monounsaturated, and polyunsaturated fatty acids. All meals were prepared in the metabolic kitchen of the General Clinical Research Center.

Results: The responses to the study diets differed by sex. In men, the fructose diet produced significantly higher fasting, postprandial, and daylong plasma triacylglycerol concentrations than did the glucose diet. The daylong plasma triacylglycerol concentration after 6 wk of the fructose diet was 32% greater in men than the corresponding concentration during the glucose diet (P < 0.001). The fructose diet had no significant effect on fasting or postprandial plasma triacylglycerol concentrations in women. The fructose diet also had no persistent effect on fasting plasma cholesterol, HDL cholesterol, or LDL cholesterol in either men or women.

Conclusions: Dietary fructose was associated with increased fasting and postprandial plasma triacylglycerol concentrations in men. Diets high in added fructose may be undesirable, particularly for men. Glucose may be a suitable replacement sugar.

Key Words: Dietary fructose • dietary glucose • healthy adults • plasma lipids • plasma glucose • serum insulin

American Journal of Clinical Nutrition, Vol. 72, No. 5, 1128-1134, November 2000 © 2000 American Society for Clinical Nutrition

Source: http://www.ajcn.org/cgi/content/abstract/72/5/1128

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