Going Nuts Over Where The Calories Go?
Can you consume extra calories and not have them count to your daily calorie balance? Of course, everyone would love this to be true, especially in regard to all those unhealthy (but good tasting) junk foods. But is this true in regard to healthy foods also? This is what we often hear lately when we are told that adding in nuts and seeds do our diet will not result in weight gain.
So, are you going nuts over where the calories go?
That is the question we should ask when we hear that adding in extra nuts and seeds does not result in weight gain. If we ingest the energy and it does not show up on us as added weight, then where did the calories go?
Well, in simple terms, if you take the calories in and they are not being stored in the body as fat, then they must be either getting burned up in the body or leaving the body, or a combination of the two. Or the calories must only be substituting for other calories. Some recent studies have verified this.
Many studies have shown that the majority of energy provided by nuts is offset by the reduction of intake of other foods. So, while we may not consciously know it, we are eating less of other foods when we consume more nuts. Several studies have shown that this effect can account for range about 55-100% of the extra calories from the nuts, with a mean of about 75%.
Second, there may be a slight increase in energy expenditure, which can account for some more of the missing energy. This may account for up to 10% of the extra calories provided by nuts/seeds.
Third, other studies have shown that the calories, in the form of the fat in the nuts, passes through the body undigested and shows up in the feces (1, 3). Not a study I want to be involved in but none the less, some important studies. This can account for up to 15% of the extra calories provided by nuts/seeds.
A recent trial compared the effects of peanut consumption in several forms on fecal energy excretion. The forms compared were whole peanuts, peanut butter, peanut oil or peanut flour. Results showed that compared to control, the percentage of fat in the feces increased significantly in the whole peanut group compared to the three other groups. The authors concluded, "Fecal fat and energy loss is greater with consumption of whole peanuts compared to peanut butter, oil or flour. This may contribute to the less than predicted change of body weight observed with peanut consumption."
This study was short term and IMHO, part of the reason there was an increase in fecal fat from the whole peanuts as compared to the peanut butter, peanut oil, and peanut flour, is because for many people, nuts are tough to chew thoroughly, and so we may not be fully digesting them, where as the butter, flour and oil do not require the same amount of chewing (if any at all) and would be easier to digest. Also, if we are not used to consuming nuts, they may be harder to digest at first due to their high fat content. However, over time, if we continue to consume them, we may become more efficient at chewing them thoroughly and digesting them.
So, when you put these three factors together, the displacement of other calories, the potential increase in energy expenditure and the undigested fat components of the nuts that passes through us, we have solved the mystery. That is exactly what a study on the energetics of nut consumption concluded, "Taken together, these findings (the three I have just mentioned) largely account for the energy provided by nuts and explain the epidemiological and clinical observations. Thus, current knowledge suggests moderate nut consumption does not pose a threat for weight gain."
Adding in a few nuts and seeds can be healthy, but don't over do them or be mislead into thinking the calories in the nuts and seeds do not count. Calories count. In most of the observational studies that are often cited as proof that nuts are healthy, the average nut consumption was 1 ounce 2-5 times a week and those consuming the nuts have a healthier lifestyle and diet..
So, just don't go nuts over the nuts!
(1) Int J Obes (Lond). 2008 Feb;32(2):322-8. Epub 2007 Oct 2. Peanut digestion and energy balance.
(2) Asia Pac J Clin Nutr. 2008;17 Suppl 1:337-9. The energetics of nut consumption.
(3) Br J Nutr. 2007;v98:651-656. Effect of chronic consumption of almonds on body weight in healthy humans.