One study in the American Journal of Clinical Nutrition compared the effects of energy controlled, moderate fat (33% energy) and low fat (18% 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 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’ total and LDL cholesterol and triacylglycerol (TG) levels in blood during this weight loss phase. The low-fat diet also resulted in a significant decrease in the ‘protective’ HDL 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, whereas those on the moderate-fat diet maintained their new lower TG blood levels. It is well known that elevated TG levels are a cardiovascular risk factor and other research has also demonstrated that during weight maintenance, low-fat diets increase TG 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. These results confirm the findings from other studies that a low-fat diet causes a decrease in the ‘protective’ HDL cholesterol even when weight loss occurs in both short and long-term studies. A moderate-fat diet, in contrast, ‘blunts’ the decrease in HDL cholesterol that usually occurs during weight loss.
This study shows that markedly lowering total fat intakes may have adverse consequences on reductions in the risk of CVD, even in response to weight loss. The authors concluded, “our results advise against a diet that provides appreciably lower than 30% calories from fat to achieve weight loss”.
There is now a strong bank of research demonstrating that regularly consuming peanuts can help reduce CVD risk. Three independent research groups have reported in the scientific literature that moderate-fat diets including peanuts can help with weight loss. Nevertheless, there is a reluctance to recommend them for weight loss, because of their fat content. This newest study effectively demonstrates that peanuts, as a major contributor to moderate-fat diets, can aid weight loss whilst protecting the heart.
Jennette Higgs, UK Nutrition Consultant for the American Peanut Council explained: “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, which is so hard to stick with anyway.”
As well as making a valuable contribution to calorie controlled weight loss diets, peanuts and peanut butter are sources of important nutrients such as potassium, magnesium, zinc, folate, vitamin E and phytosterols. Peanuts have a very low glycaemic index (GI) of 14, are a good source of vegetable protein and fibre and are naturally low in carbohydrate - all factors that aid effective a href="/index.cfm?currpage=news&subsection=top10&department_id=18&code=24030">weight loss.
The authors of this study “support the recommendation of a weight loss diet that has a moderate total fat content and conforms with current guidelines for saturated fat, to achieve the most desirable CVD risk profile”.
If you're wondering how this compares to your weight loss plan , our nutritionist Dr Barbara Wilson, has the numbers: "Our weight loss plans are designed to provide around 30% energy from fat and 50-60% energy from carbohydrates - this would be comparable to the moderate-fat diet described above. Peanuts are a great addition to your diet but do remember to keep an eye on that portion size."