If people start to eat a little more nuts every day, they will not become fatter in the long run and even lose weight. This follows from an epidemiological study that American nutrition scientists recently published in BMJ Nutrition, Prevention & Health. A special effect is brought by an increase in the number of the best nuts for weight loss in the diet if it occurs due to their replacement of french fries and chips.
A Study of the Effect of Nuts on Weight Loss
Researchers associated with Harvard University used the data collected from 1986 to 2011 in three large epidemiological projects, as well as to study the status of medical staff [HPFS] and to study the health indicators of nurses [NHS] I and II.
The data collected in three prospective, longitudinal cohorts among healthcare providers in the United States was analyzed. These included 27,521 men (a follow-up study by health workers, 1986-2010), 61,680 women (a study of the health status of nurses, 1986-2010) and 55,684 young women (a study of the health of nurses II, 1991-2011), which did not have chronic diseases at the initial stage of the analysis.
They studied the relationship between changes in nut consumption over 4-year intervals and simultaneous weight changes over 20-24 years of observation using multidimensional linear models with an unstructured correlation matrix to account for intraindividual repetitive measures. 21 322 people reached the body mass index according to the classification of obesity (BMI ≥30 kg / m2) at the end of the follow-up observation.
Changes in weight growth with increasing consumption of nuts
The average weight gain in three cohorts was 0.32 kg per year. An increase in the proportion of nuts for weight loss diet by 0.5 servings per day (14 g) was significantly associated with a decrease in body weight gain over a 4-year interval. An increase in the absorption of the best nuts for weight loss: walnuts and other tree nuts by 0.5 servings/day was associated with a significantly lower risk of obesity. Increasing the number of nuts eaten reduced the risk of increasing weight by ≥2 kg or ≥5 kg. In the substitution analysis, replacing 0.5 servings/day of red meat, processed meat, french fries, any desserts or chips with nuts was associated with less weight gain.
The combined, joint result of the three studies used:
According to the figures below, the study participants became slimmer in the first place when they replaced french fries and chips with nuts. That is, one high-calorie food was replaced by another.
Why nuts are good for weight loss
A possible explanation for the smaller effect of nuts on weight, in comparison with other high-calorie foods, is that our body does not absorb all the energy contained in them. A prerequisite for this explanation is the results of the 2012 experiment in which it was established that the actual energy obtained from the use of whole raw almonds was lower than stated in the literature by 32%. (1)
However, in another experiment of the same researchers conducted in relation to pistachios, the numbers were much more modest. The measured energy density of pistachios turned out to be only 5% less than the currently accepted value. (2)
Unfortunately, there is no similar information on other types of nuts.
In addition, it must be borne in mind that nuts require significant efforts to process them in the oral cavity. Chewing gum, for example, can cause dietary compensation by lowering the rate of ingestion. A high fiber diet can delay gastric emptying and increase satiety, suppress hunger, and desire to eat. Fiber nuts also provide greater binding of fatty acids in the intestines, which leads to increased caloric fecal excretion (more fat comes out with feces).
Another possible explanation is as follows: the increased amount of unsaturated fats in nuts increases the oxidation of fatty acids increases thermogenesis and resting energy consumption, which can also help reduce body weight gain.
Details on this mechanism are described in the article “Changes in nut consumption influence long-term weight change in US men and women,” published here: (3).
The Bottom Line
“The increased total consumption of nuts in general or of certain types of nuts (including peanuts) turned out to be associated with lower long-term weight gain, despite the fact that they are energetically dense,” the researchers conclude.
“Including nuts for weight loss diet can be an effective strategy for making possible changes to your diet for the primary prevention of obesity.“
- Discrepancy between the Atwater factor predicted and empirically measured energy values of almonds in human diets. Novotny JA, Gebauer SK, Baer DJ. Am J Clin Nutr. 2012 Aug;96(2):296-301.
- Measured energy value of pistachios in the human diet. Baer DJ, Gebauer SK, Novotny JA. Br J Nutr. 2012 Jan;107(1):120-5.
- Changes in nut consumption influence long-term weight change in US men and women. BMJ Nutrition, Prevention & Health 2019;2: doi: 10.1136/bmjnph-2019-000034.
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