Can Peanuts Help Reduce Body Fat?
You might assume that because peanuts contain fat, they must add body fat and thus contribute to obesity. Not true.
Researchers from Brazil’s Federal University of Viçosa have determined that the regular consumption of peanuts decreases body fat and increases fat oxidation – at least among obese men.
The research tested 55 adult men who were obese, and between the age of 18 and 50 years old. The men had an average body mass index of 29.7 kg/m2.
The men were divided into three groups. All three groups received a low-calorie diet for four weeks. One group ate 56 grams per day of conventional peanuts with their diet. Another group ate 56 grams a day of high-oleic peanuts in addition. The third group ate the low-calorie diet without peanuts.
After four weeks, the average body fat decreased in both peanut groups. But the high-oleic peanut group’s average body fat levels significantly decreased, further than the other two groups.
The researchers also found that the high-oleic peanut group had increased total lean mass as a percentage of body mass.
Both peanut groups also had significantly higher after-meal (postprandial) fat oxidation than before the trial and compared to the control group. But the high-oleic peanut group had higher fat oxidation than the conventional peanut group.
What is fat oxidation?
Higher levels of fat oxidation are related to leaner body fat and eventual weight loss because fats are broken down into free fatty acids which can be used for energy production. Foods that increase fat oxidation include foods greater in monounsaturated fat. Other fats, such as saturated fats, lower fat oxidation.
Ultimately, an increase in fat oxidation rates with a concurrent reduction in carbohydrate oxidation rates has been shown to reduce body fat.
This was found in a study from the Curtin University of Technology in Perth Australia. The researchers tested 14 men over a two-week period with body mass indices between 20 and 32 kg/m2. The researchers gave each subject breakfast meals with different fat composition and tested their after-meal insulin, glucose and fat oxidation levels.
The research found that the breakfast meals with higher monounsaturated fats (in the form of olive oil) significantly increased fat oxidation rates while significantly reducing carbohydrate oxidation rates. The monounsaturated group also had greater caloric burning – thermogenesis rates – than the saturated fat group.
Peanuts are high in monounsaturates
A serving (144 grams – one cup) of conventional peanuts – organic or conventionally grown – will typically contain about 75 grams of fat in a serving, with 50% of it as monounsaturated fat. About 12.5 grams will be saturated – close to 17% of its fat content – and 22 grams will be polyunsaturated.
In comparison, a serving (1 cup) of olive oil contains 216 grams of fat in a 216 gram serving, with 30 grams of that fat being saturated – about 14% of its fat content – and 23 grams will be polyunsaturated. But olive oil will contain about 73% monounsaturated fat – or about 158 grams.
In other words, peanuts are not that far off of olive oil in terms of their fat content – making peanuts a healthy addition to the diet.
And this higher content of monounsaturated fat and relatively low level of saturated fat gives peanuts a high score for producing greater fat oxidation.
High-oleic peanuts are even better
But the high-oleic peanut – this contains about 80% monounsaturated fats. The high-oleic peanut was traditionally hybridized (not genetically engineered) by University of Florida peanut breeder Dr. Dan Gorbet. The hybrid is beginning to see increased plantings throughout the U.S.
Dr. Gorbet’s crossbreeding started back in 1970. He identified different peanut varieties with higher oleic content and crossbred them to establish the high-oleic peanut plant.
The new hybrid is also more disease resistant and the peanuts naturally have a longer shelf life.
University of Florida filed for a patent for the high-oleic peanut – called SunOleic 97R – in 1987, just after the high-oleic sunflower – another natural crossbred hybrid – was also filed for patent. And because the high-oleic sunflower patent was held up in litigation for over a decade, the US Trademark Office refused to grant the patent for the SunOleic 97R peanut until 1998.
Peanuts are also nutrient powerhouses
Both the conventional peanut and the high-oleic peanut are nutrient dense. Peanuts contain considerable amounts of alpha-tocopherol vitamin E (50% Daily Value per serving), 100% Daily Value for niacin, 33% DV for vitamin B6, 43% DV for folate, 17% DV for pantothenic acid and is a significant source of choline (good for nerves) and other B vitamins.
A serving of peanuts also contains significant mineral content, including calcium, iron, magnesium, potassium, zinc, copper, manganese and selenium. And a serving of peanuts will contain 40 grams of protein, including many of the essential amino acids.
Research from Tufts University has confirmed that peanuts also contain numerous phytonutrients. These include phenolic acids, flavonoids and stilbene resveratrol. Peanuts contain 84 micrograms of resveratrol per 100 grams. Peanuts are also a source of proanthocyanidins – shown to reduce artery inflammation.
Peanuts are extremely healthy, but organic peanuts – whether conventional or high-oleic – should be sought out. Conventionally-grown peanuts will be sprayed with pesticides and fungicides such as azoxystrobin, tebuconazole and flutolanil. Peanuts will sometimes also be treated with fungicides during processing.
As for peanut sensitivities, there are natural solutions:
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Piers LS, Walker KZ, Stoney RM, Soares MJ, O’Dea K. The influence of the type of dietary fat on postprandial fat oxidation rates: monounsaturated (olive oil) vs saturated fat (cream). Int J Obes Relat Metab Disord. 2002 Jun;26(6):814-21.
Chen CY, Blumberg JB. Phytochemical composition of nuts. Asia Pac J Clin Nutr. 2008;17 Suppl 1:329-32.
Spence C. In A Nutshell: A Better Peanut: The SunOleic 97R Peanut Developed At Florida Offers Health And Financial Benefits To Growers, Sellers And Eaters.