June 19, 2014

Are Nuts Fattening?

The question ‘are nuts fattening‘ is one I get asked regularly.

In fact, almost every time I suggest that people should have nuts as a snack, I get some opposition. It’s an interesting one that requires us to take a closer look at the facts…

What the studies say

No-one’s going to argue that nuts aren’t high in fat — they are.

But, many people assume you shouldn’t eat them when trying to lose weight. Studies have confirmed, however, that people who eat nuts have a lower body weight than those who don’t.

Since almonds are a pretty popular nut, let’s think about them for a minute.

First study:

  • 81 healthy adults 
  • Given 60 grams of raw or dry-roasted almonds for 6 months
  • Participants were expected to gain 14 lbs
  • Instead weight gain was only 1.3 lbs for men, and 0.3 lbs for women

Second study:

  • 20 healthy, overweight women
  • Given 65 grams of almonds for 10 weeks
  • The mathematical theory of “energy consumed minus energy expended equals weight gain” predicted that women should gain 7.5 pounds
  • Instead, the participants’ weight did not change at all. In fact, their weights went on average from 155.9 lbs to 154.6 lbs.
So, it seems clear the impact of nut consumption on weight is either negligible, or non-existent. Also remember that in these studies, participants were not on any sort of diet.

Nothing had changed in their lifestyle other than the inclusion of nuts.

This begs the question, what would the effect of nuts be on weight if they were also part of a weight management regimen?

Other studies have shown that replacing carbs with almonds in a weight loss program leads to greater reductions in body weight and BMI, waist circumference and fat mass. Therefore, compelling evidence suggests you can include nuts in your regular or weight loss diet without fearing weight gain.

So, how can this paradoxical phenomenon be explained?

Are nuts healthy? 

3 reasons why nuts aren’t fattening:

1. Nuts have high satiety properties

People who eat nuts report sharp reductions in appetite. This is because nuts have a high fullness indexStudies have shown that when you eat nuts there is a reduction in energy intake. In fact, about 70% of the energy provided by nuts is offset by lower food consumption at subsequent meals.

2. Nuts are not absorbed efficiently

The fat contained in nuts is not efficiently absorbed in the gastrointestinal tract. This manifests itself as elevated fecal fat loss. It’s thoughts that up to 20% of the lipid content of whole nuts will be lost in the stool. This is around 10-20% of the energy contained in nuts.

3. Nuts increase metabolism

Regular consumption of nuts increases resting energy expenditure (REE). This is the minimal energy we spend in one day at rest — just doing nothing.

In one study, people who ate 500 calories per day from peanuts for 19 weeks, showed an 11% increment in REE.

To get an idea of what effect a REE increase of this magnitude would have on your weight, let me explain:
  • The average woman in the US (30 year-old, 5’ 4’’ tall who weighs 160lbs) has a REE of 1,511 calories per day
  • An increase of 11% in her REE means her body burns an extra 166 calories per day
  • She can choose to “eat” these additional calories without worrying about gaining weight, or “leave” them and lose weight at a pace of 1.4 lb per month, or 17 lb per year
  • And, that is by just including nuts in the diet, with no other lifestyle changes


Well, although nuts are among the most energy dense foods around, studies show little to no impact on body weight.

This is great news, because nuts have so many health benefits. Therefore, excluding them from your diet would be crazy! Next time you feel like indulging, go for whole, raw, unsalted nuts, and don’t feel guilty about it!


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