Publishing their findings in the February issue of the American Journal of Clinical Nutrition, scientists at the Pennsylvania State university report that a peanut rich diet high in monounsaturated fat resulted in a 14 per cent reduction in cardiovascular risk, compared to a 9 per cent reduction for the low fat diet.
They compared the effects of energy controlled, moderate fat (33 per cent energy) and low fat (18 per cent energy) diets on cardiovascular disease (CVD) risk factors during a 6 week weight loss phase, followed by a 4 week weight maintenance phase, in 53 overweight and obese men and women.
Both experimental diets were low in saturated fat - 7 per cent energy ?and carbohydrates replaced saturates in the low fat diet to provide the typical low fat, high carbohydrate, 63 per cent energy, diet.
In the moderate fat diet, monounsaturated fats provided mainly from peanuts, peanut butter and peanut (groundnut) oil, replaced the saturates.
Weight loss on both diets was controlled and not significantly different, averaging above 2lb/week during the weight loss phase and both diets effectively reduced the bad LDL cholesterol and triacylglycerol (TG) levels ?a cardiovascular risk factor - in blood during the weight loss phase.
But the researchers found that the low fat diet also resulted in a significant decrease in the HDL, 'good?cholesterol levels, whereas the moderate fat diet subjects experienced no significant change in HDL levels.
During the subsequent weight maintenance phase, those on the low fat diet showed a complete reversal in TG levels, returning to pre-diet levels. The scientists report that those on the moderate fat diet maintained their new lower TG blood levels.
Neither group showed any further change to HDL levels during the weight maintenance phase. By the end of the study, those in the low fat group had a lower HDL level than at the start, whereas the moderate fat group experienced no significant change.
The researchers conclude that their results confirm findings from other studies that show a low fat diet could decrease the protective?HDL cholesterol even when weight loss occurs in both short and long-term studies. In contrast, a moderate-fat diet can serve to stop the decrease in HDL cholesterol that usually occurs during weight loss.
'Our results advise against a diet that provides appreciably lower than 30 per cent calories from fat to achieve weight loss?/i> said the lead author of the study Christine Pelkman.
Commenting on the reluctance to recommend peanuts for weight loss because of their fat content, Jennette Higgs, UK nutritionist for the American Peanut Council said : 'This study shows that it is no longer appropriate to exclude good sources of monounsaturated fat such as peanuts from weight loss diets.
Weight loss and weight maintenance is achievable on a higher fat diet, including daily peanuts. What's more, a higher fat diet also offers greater cardio protection than the typical low fat diet.?/i>
Full findings of the paper 'Effects of moderate-fat (from monounsaturated fat) and low fat weight loss diets on serum lipid profile in overweight and obese men and women?/i> by CL Pelkman et al are published in the American Journal of Clinical Nutrition, 79:204-12 (2004).
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