Somehow the human body uses the energy from peanuts in a different way than energy from other foods. Either it doesn’t absorb all the energy the peanuts have, or it burns the calories quicker, according to an experiment that nutritionists at the University of South Australia have published in Nutrients.
The researchers got 61 healthy subjects to eat 2-3 packets of peanuts every day for 12 weeks. The packets contained 56-84 g peanuts. The subjects were to continue with whatever exercise they did and were given no other dietary instructions, such as to leave things out in compensation for the extra peanut intake.
The researchers used high-oleic peanuts. These contain slightly less saturated fat and les polyunsaturated fatty acids than ordinary peanut, and more monounsaturated fat. The fatty acid composition of high-oleic peanuts strongly resembles that of olive oil.
Apart from that, high-oleic peanuts contain the same amounts of protein, carbohydrates, fibre, vitamins and minerals as ordinary peanuts.
The researchers also monitored the subjects during a different 12-week period, during which they ate no peanuts.
In the 12 weeks during which the subjects ate packets of peanuts every day, their energy intake increased by about ten percent. They consumed above all more monounsaturated fatty acids.
In theory the subjects should have put on 1.9 kg in weight after 12 weeks of eating peanuts. They actually only gained half a kilogram.
The addition of the peanuts to the diet did not however result in a thicker waist or a significant increase in the body fat percentage.
When the researchers did their calculations they noticed that the daily peanut consumption led to a change between daily energy intake [shown above in kilojoules] and bodyweight. If the subjects had eaten peanuts instead of other foods in the diet, they probably would have lost weight.
The researchers suspect that the body doesn’t absorb all the energy that peanuts have. Another possibility is that the body’s energy expenditure rises when peanuts are added to the diet.
“Recommendations can be made to incorporate moderate amounts of high oleic peanuts as part of a healthy diet with unlikely detrimental effects on body weight especially if substituted for other foods”, the researchers conclude.
The Australians’ researcher was partly funded by the Australian government and partly by the Peanut Company of Australia, [pca.com.au] the biggest manufacturer of high-oleic peanuts in Australia.
Effect of 12 Weeks High Oleic Peanut Consumption on Cardio-Metabolic Risk Factors and Body Composition
Epidemiological evidence indicates an inverse association between nut consumption and obesity, inflammation, hyperlipidaemia and glucose intolerance. We investigated effects of high oleic peanut consumption vs. a nut free diet on adiposity and cardio-metabolic risk markers. In a randomised cross-over design, 61 healthy subjects (65 ± 7 years, body mass index (BMI) 31 ± 4 kg/m2) alternated either high oleic peanuts (15%–20% of energy) or a nut free diet for 12 weeks. Body composition and mass, waist circumference, C-reactive protein (CRP), lipids, glucose and insulin were assessed at baseline and after each phase. Repeated measures analysis of variance (ANOVA) compared the two diets. Consistent with other nut studies, there were no differences in lipids, CRP, glucose and insulin with peanut consumption. In contrast, some reports have demonstrated benefits, likely due to differences in the study cohort. Energy intake was 10% higher (853 kJ, p < 0.05), following peanut consumption vs. control, attributed to a 30% increase in fat intake (p < 0.001), predominantly monounsaturated (increase 22 g, p < 0.05). Despite greater energy intake during the peanut phase, there were no differences in body composition, and less than predicted increase (0.5 kg) in body weight for this additional energy intake, possibly due to incomplete nutrient absorption and energy utilisation. Source: http://www.mdpi.com/2072-6643/7/9/7381