Peanut intake may help with weight loss

In the context of an energy-restricted diet, a weight-loss diet involving daily consumption of 70 g of lightly salted dry-roasted peanuts yielded similar weight loss results as a traditional low-fat weight-loss diet after 6 months in adults at high risk for type 2 diabetes (T2D), a study has shown.

“Both diets improved fasting glucose, insulin, HOMA-IR*, and HbA_1c, [but there were] no differences … between the two weight-loss diets,” noted the researchers. In terms of systolic blood pressure (SBP) reduction, the peanut-containing diet outdid the traditional one, which could eventually lead to reduction in cardiovascular disease (CVD) risk.

The study randomized 107 participants (mean age 58 years, 65 percent female, BMI 33 kg/m²) 1:1 to either the peanut-enriched or traditional (control) weight-loss diet for 6 months. Participants in the peanut arm were advised to consume 35 g of lightly salted dry-roasted peanuts 30 minutes before two main meals per day. Those in the control cohort were provided with education to follow a low-fat diet, did not have preloads, and were advised to avoid peanuts and peanut butter throughout the trial. [Nutrients 2022;14:2986]

All participants were given dietary counselling to limit energy intake to 1,300 (women) and 1,700 kcal/day (men) and were asked to maintain constant exercise patterns throughout the study.

At 6 months, mean weight loss from baseline was 6.7 and 6.6 kg in the respective peanut and control arms, yielding no difference between arms (mean difference, –0.12; p=0.92).

The peanut arm also demonstrated reductions from baseline fasting glucose (from 5.12 to 4.99 mmol/L), fasting insulin (from 10.89 to 8.14 u/mL), HOMA-IR (from 2.49 to 1.88), and HbA_1c (from 5.61 percent to 5.48 percent) at 6 months. Similarly, the corresponding baseline values of these glycaemic markers in the control arm (5.13 mmol/L, 11.42 u/mL, 2.66, and 5.61 percent) dropped at 6 months (4.90 mmol/L, 7.33 u/mL, 1.6, and 5.49 percent, respectively). When comparing the results between arms however, no differences were seen.

SBP

Baseline SBP dropped at 6 months in both the peanut (–9.46 mm Hg; p<0.001) and control arms (–4.13 mm Hg; p=0.007). The reduction in the peanut arm was substantially greater than the corresponding change seen in the control arm (mean difference, –5.33 mm Hg; p=0.008).

The findings on SBP deviate from those seen in trials showing that peanut intake had no effect on SBP. [Am J Clin Nutr 2015;101:966-982; Crit Rev Food Sci Nutr 2020;60:1123-1140] “While the results of the present study diverge from prior evidence, it should be noted that relatively few studies have examined the effect of peanuts on BP, and limited studies have evaluated cohorts at high risk of T2D undergoing weight loss,” said the researchers.

“Since weight loss was comparable between [arms], diet-related differences likely explain the SBP lowering observed in the peanut arm,” they continued. “The higher-MUFA**/lower-carbohydrate intake in the peanut arm may have contributed to the observed SBP lowering.”

Moreover, the reduced sodium intake and increased potassium intake in the peanut arm may have factored in the SBP reduction.

High satiety value

Dietary approaches to achieve sustained weight loss in adults with overweight and obesity are critical for reducing T2D and CVD risk. An energy-restricted diet is usually a first-line intervention, but several factors affect its sustainability. [Circulation 2014;129(Suppl S2):S102–S138] “A key challenge is feelings of hunger because of the lower satiety value of many weight-loss diets,” the researchers noted.

Two of the dietary strategies with greater satiety value are higher-protein diets and consumption of a preload prior to main meals. Nuts – although often excluded from weight-loss diets because they are energy-dense and may thus promote weight gain – have high satiety value, suppress hunger, and increase fullness. [J Am Coll Cardiol 2017;69:1172-1187; Am J Clin Nutr 2014;100(Suppl S1):412S-422S]

“Collectively, the results of this trial suggest that 70 g/day of peanuts may be included in an energy-restricted weight-loss diet without attenuating weight loss over a 6-month period,” said the researchers.