Why Eating Nuts Will Not Make You Fat

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You have probably heard before that nuts are high in fat, therefore not something you want to eat if you are trying to lose weight. In a society where popular dieting consists of obsessing over counting calories, nuts are considered by many a big no-no because of their caloric value.


Interestingly enough, nuts have been given a bum rap about their fat content.  Although they are indeed super high in fat and considered “energy-dense,” studies show that they do not necessarily contribute to weight gain.  In fact, scientific evidence reveals that the addition of nuts into your diet may actually help you lose weight.

In a study published in the Journal of Nutrition in 2008 [1], the consumption of nuts and its impact on weight gain is explored.  The findings conclude that eating nuts will not necessarily make you gain weight.  In fact, you can actually lose weight more efficiently if you eat nuts than if you only followed a low-fat diet.  This contradicts a lot of what was previously believed about nuts and weight gain.

Here’s a look at this and other similar studies:

The Scientific Verdict on Nuts and Weight Loss:  What the Studies Say

Whereas it used to be thought that nuts contributed to weight gain, studies are actually proving that people who consume more nuts than others are actually less obese.  One way to support this conclusion is to examine an individual’s Body Mass Index (BMI) and its relationship to nut consumption.  BMI measures your body fat based on weight and height.  Epidemiologic studies find evidence that adult nut eaters have a lower BMI than non-nut eaters.  Thus, nut consumption is associated with a lower BMI, which undermines previous ideas about nuts being bad for your weight because of their fat content.

There appears to also be a number of benefits for nut eaters who aspire to lose weight. One such benefit is overall greater weight loss.  Several controlled clinical trials have found evidence that nuts are not necessarily responsible for weight gain.  Some intervention studies have shown that adding nuts to your daily diet actually has a positive effect in weight management. In the study, people who consumed almonds in a weight reduction program lost more weight and BMI than individuals who consumed complex carbohydrates. Nuts were not only superior in preventing heart disease, but their addition to a moderate-fat diet was more effective in weight loss programs.

Another benefit of eating nuts is that people who consume them have a greater chance of sticking to their diet.  Nut eaters tend to overall eat better foods throughout the course of their diets, while individuals who are on low-fat diets are less likely to maintain a quality diet.  One possible explanation is that low-fat foods may be less calorie-laden but not necessarily healthy, whereas nuts are natural.  This will have an impact on how the body processes and breaks down the foods.  Also, a lot of low-fat foods will not make you feel full, which leads to a person eating more food to compensate.

Why Aren’t Nuts Fattening?

We probably can all agree that nuts are high in fat, but why aren’t they fattening?  The simple answer is that food shouldn’t necessarily be measured by its fat content or caloric value when predicting weight gain or loss, since different foods affect the body differently.

According to the study, there is evidence that nuts have a limited, if any, impact on weight gain.  They propose three reasons based on scientific evidence as to why nuts may actually contribute to weight loss and/or augment weight loss.

Satiety and Dietary Compensation

Nuts have high satiety properties, which mean consuming them gives you the feeling of fullness.  If we feel full, we are less likely to continue eating.  Tests using peanuts, almonds, and chestnuts have shown that their consumption reduces hunger.

Satiety can also be looked at by examining its dietary compensation.  Studies show that the majority of energy given by nuts is actually later offset by the fact that people will eat less of other foods at subsequent meals.  In other words, although nuts may be high in calories, because they fill us up we eat less food overall during the day, which means fewer calories.  Many people think low-fat diets are the key to weight loss, but the reality is that low-fat foods are not necessarily going to help you lose weight if they leave you starving for more food.

Efficiency of Energy Absorption

Studies show that the efficiency of energy absorption from nuts is limited. This is manifested as elevated fat loss in the feces of nut consumers.  In other words, people who eat nuts pass a good percentage of the fat through their bodily waste.  When whole nuts are consumed, a greater percentage of the lipids are lost in stool.

For example, 17.8% of the lipid load was lost when consuming whole nuts.  When peanut butter was consumed, 7% of the lipids were lost in stools.  One explanation may be that cells that are not ruptured during mastication can actually pass through the gastrointestinal tract without releasing the oils they contain.  Thus, not all of the fat contained in nuts is getting absorbed by your body.

Increased Resting Energy Expenditure (REE)

Studies show eating nuts augments your energy expenditure.  Resting energy expenditure (REE) is the amount of calories your body needs in a 24-hour period during which you do nothing but rest.  Chronic consumption of peanuts has been associated with elevated REE.

In a one-week trial, it was found that eating peanuts led to an 11% increment in REE in the span of 19 weeks.  To put this in perspective, an average woman in the United States (30 years old, 5 feet 4 inches tall, weighing 160 lbs) has an REE of 1511 calories/day.  If her REE were to increase by 11%, her body would burn an extra 166 calories a day.  If she were to “leave” these calories and not replace them by eating more food than usual, she would actually experience a weight loss of 1.4 lbs a month, or 17 lbs a year.  This weight loss would be as a result of simply replacing some of her daily food with nuts.  These results demonstrate the potential of nuts in a weight loss program.

The study concludes with estimates of the following:  55-75% of energy contributed by nuts is offset by dietary compensation, 10-15% offset by fecal loss, and 10% due to energy expenditure.  The findings show that energy-dense foods like nuts are not necessarily going to make you fat, but in fact may help you lose weight.  Thus, the evidence contradicts many common assumptions about nuts being fattening.

If you want to start incorporating nuts into your diet for weight loss, make sure you pick up nuts that are raw and unsalted.  If you eat nuts in moderation, you do not have to worry about packing on the weight, and in fact may experience weight loss.  Eating a small handful of nuts is a great way to keep you full in between meals and prevent unhealthy snacking.

About the author: Jessica Crowds is a biologist, writer, and a natural weight loss advocate.  He has a keen interest in food science, nutrition, and natural weight loss remedies.


1. Mattes RD, et al. Impact of peanuts and tree nuts on body weight and healthy weight loss in adults. J Nutr 2008; 138:1741S-1745S

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