Why the notion that eating nuts causes weight gain is, well, nuts!

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This week, I saw a story reporting some American research in which an extract of a pine nut from Korea was found to increase the level of the appetite suppressing substances cholecystokinin and glycagons-like peptides. No doubt, some company or other will attempt to exploit this finding with a wonder-pill based on this extract (actually pinolenic acid) for the purposes of weight loss.

I reckon those keen to get the get better control of their appetite and weight may, however, do this by simply eating more nuts. The idea that something from nuts may actually help weight control seems a little counter-intuitive at first, bearing in mind the reputation nuts have for being both fatty and fattening. However, studies show that nuts tend not pile on the pounds at all. Nuts are a nutrient-packed, healthy ‘primal’ food, and something that experience shows that satisfy the appetite and prevent overeating at meal time. What follows, is a round-up of the health effects of nuts, including details of research which has supports the notion that nuts are not fattening.

Observer column – 24th November 2002

During a food shopping trip this week I became acutely aware that the festive season is upon us. In addition to the glut of Christmas puddings and cheese and port ensembles, my local supermarket has seen an influx of nut selections typical at this time of year. Tasty though they are, nuts tend not to enjoy the healthiest of reputations. Packed full of fat and calorie-dense, doctors and dieticians are often quick to warn us that nuts have the capacity to harm the heart and widen the waistline. However, a closer look at the nutritional research reveals that nuts not the dietary demon they are often seen to be. Studies show that eating nuts can have considerable benefits for heart health, and are unlikely to add to any excess baggage we may be carrying. Contrary to popular opinion, the evidence suggests that nuts are one food worth shelling out for whatever the time of year.

Nuts are an intensely fatty food, with about 80 per cent of the calories they offer coming from fat. While this fact might seem somewhat unpalatable at first sight, it should be borne in mind that the types of oils found in nuts such as almonds, cashews, walnuts, hazelnuts and brazil nuts is predominantly of healthy monounsaturated and polyunsaturated types. One potential effect of these beneficial fats is to reduce blood levels of low-density lipoprotein (LDL) cholesterol ” the type of cholesterol believed to have artery clogging potential in the body.

Nuts are also rich in fibre and natural plant substances known as sterols, both of which are believed to have cholesterol quelling potential by helping to block its absorption from the gut. Although many people with raised cholesterol levels are warned off eating nuts, the evidence shows that this advice is simply not based in science. Several studies show that including nuts in the diet has the ability to lower LDL cholesterol levels by about 10 per cent ” a reduction that would be expected to confer substantial protection from the nation’s number one killer.

In addition to their ability to reduce cholesterol levels quite naturally, nuts are also rich in nutrients believed to have heart disease protective properties such as vitamin E, magnesium, copper and potassium. It is perhaps no wonder then that five large studies have found that those who include nuts in their diet tend to be at lower the risk of heart disease. One study found that women consuming at least five ounces (about 125 g) of nuts each week had one-third fewer heart attacks compared to women who rarely or never ate nuts. Another study, this time in men, found that individuals eating two or more one-ounce servings of nuts per week were at a 30 per cent lower risk of death due to heart disease compared to men who consumed nuts less often.

For the very best health effects, nuts are probably best taken in their raw (unroasted) and unsalted state. Despite being rammed full of calories, it appears that they are unlikely to inflate our weight: more than one study has found that when nuts are added to the diet, the body generally compensates by eating less of other foods. In stark contrast to their rather unwholesome reputation, the evidence suggests that nuts are a supremely healthy and nutritious food. For those pondering the nut selections in their local supermarket, my advice is to get cracking.

Nutrition News from Observer Column – 3rd November 2002

Several studies suggest that eating more nuts is associated with a reduced risk of heart disease. However, nuts are intensely calorific on account of their high fat content, and are therefore generally regarded as a fattening food. To test this idea, scientists recently fed individuals 50 g (320 calories) of almonds each day for a period of six months to see what effective this had on their weight. During the almond-feeding period, the average weight gain was 1 lb., a small increase that was not statistically significant. Not only this, but those who experienced this weight gain tended to be those who were not overweight to begin with. Food diaries and interviews revealed that when individuals increase their consumption of nuts, they automatically compensate by eating less of other foods. The results of this study suggest that the notion that nuts are an inherently fattening food is unfounded.

Nutrition News from Observer Column – 22nd September 2003

Nuts are a natural food, and rich in many heart-healthy nutrients including monounsaturated fat, magnesium, potassium and fibre. Several studies have found that nut-eating is associated with significantly reduced risk of heart disease in both men and women. Despite this, many are still wary of eating nuts on account of their highly calorific nature and reputation for widening the waistline. A recent study published in the European Journal of Clinical Nutrition reviewed 13 individual studies that assessed the effects of nuts on weight (1). All the studies in which nuts were used to replace other foods found no increase in weight. However, what is perhaps more surprising is that even when nuts were added to an existing diet, all but one study found no tendency to lead to weight gain. Researchers have suggested that this observation may be related to the ability of nuts to satisfy the appetite and reduce overall intake of food. There is also some evidence that consuming healthy fats (such as those found in nuts) may actually help the body to burn fat. Whatever the explanation, the evidence shows that despite being fatty, nuts do not appear to be fattening.


1. GarcÃa-Lorda P, et al. Nut consumption, body weight and insulin resistance. European Journal of Clinical Nutrition 57, S8 – S11

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