More evidence comes in that demonstrates a calorie is not a calorie

The calorie principle has been a central theme in weight loss advice for some decades, and encourages individuals keen to lose weight or maintain their weight to avoid calorific foods. However, for a variety of reasons, calorific foods may not be fattening, and in fact might even promote weight loss. Some of the most important mechanisms at play here were explored in a study which I reported on in October, which specifically examined the relationship between nut eating and weight.

In summary, this study found that nuts are not, generally speaking, at all fattening. And this appears to have to do with the following major factors:

1. Nuts tend to satisfy the appetite

2. Nuts have relatively low glycaemic index, and therefore tend not to stimulate much in the way of secretion of insulin (the chief fat storage hormone)

3. Nuts stimulate the metabolism

4. Not all of the fat in nuts is absorbed from the gut

Support for the idea that nuts are not fattening has come from a study that is currently in press at the American Journal of Clinical Nutrition [1]. This study of over 50,000 women over an 8-year period found that eating more nuts was not associated with weight gain. In fact, women eating nuts two or more times each week tended to put on less weight and be less prone to obesity compared to those who rarely ate them. One explanation here, of course, is that women less prone to weight gain are perhaps less likely to feel restrained regarding their intake of ‘fattening’ foods such as nuts. However, because of the mechanisms listed above, there is reason to believe that nut-eating might genuinely promote weight maintenance or even weight loss.

One way to test this theory is to actually feed people nuts to see what effect this has on their weight. This was done recently in a study published in the Scandinavian Journal of Clinical and Laboratory Investigations [2]. In this study, adults were fed with peanuts in addition to their normal diet at a ‘dose’ of 20 calories of peanuts per Kg of body weight per day. (Peanuts are not, strictly speaking, a nut. They are legumes, but have a nutritional make-up akin to tree nuts). That’s a lot of additional calories. However, despite this, after two weeks, weight had not increased significantly. Waist circumference did not increase either. Metabolic rate, however, saw a significant rise.

Now, while this group were munching on peanuts, another group was adding a similar number of calories into their diets in the form of candy (high sugar snacks). Yet the results were quite different: both weight and waist circumference increased significantly. Metabolic rate did not rise, but levels of supposedly unhealthy LDL cholesterol did.

While the number of individuals in this study was small and the study duration was short, what we clearly have here is two very different results from the addition of the same amout of two very different foods. It provides, yet more evidence, to support the idea that a calorie is not a calorie.


1. Bes-Rastrollo M, et al. Prospective study of nut consumption, long-term weight change, and obesity risk in women. Am J Clin Nutr (April 29, 2009).

2. Claesson AL, et al. Two weeks of overfeeding with candy, but not peanuts, increases insulin levels and body weight. Scand J Clin Lab Invest. 24th April 2009 [epub ahead of print]

13 Responses to More evidence comes in that demonstrates a calorie is not a calorie

  1. Wendy 1 May 2009 at 6:06 pm #

    Hmmm…….it seems like I am up the creek without a paddle when it comes to alot of the information like this. I am allergic to nuts, seeds, and fish. I do not seem to be able to lose any weight no matter what I do, even with xenical and reductil (not at the same time, obviously) 🙁

  2. In a Nutshell 1 May 2009 at 6:16 pm #

    John, I have been taking an interest in metabolism and the notion that ‘metabolic dysfunction’ arises from unsatisfactory human diets and is most evident as manifested by obesity and type 2 diabetes.
    Your own book, “The True You Diet” emphasises the benefits of getting the right quality and the right balance of macro-nutrients (ie, carbohydrate, protein, and fats/oils)
    I have also found books by Barry Sears in his ‘Zone’ series to be both highly instructive and highly readable in this regard.
    I see here and elsewhere the anti-carb debate rages on. A lot is down to the Atkins legacy.
    In keeping my library service exceedingly busy I am trying to get fully up to speed on this. Already I lean towards the notion that carbohydrates are a healthy component to the human diet. Problems arise after too long on a diet which places too high a dependency upon specifically very high GL carbohydrate staples.
    ‘The 7 day Zone Diet’, Barry Sears gives a comprehensible systemic explanation as to why eating macro-nutrients in the correct balance pays dividends. And of course, micro-nutrients and trace elements, largely as available from veg and fruit, are important too.
    Within a few days of selecting (and practicing) advice from both these books, and in making a little effort to exercise consistently, I felt generally ‘healthier’ in many regards. My metabolism was so ‘stoked up’ I felt noticeably hotter in bed. Such energy expenditure amounted a reduction on the scales.

    Of our modern, arguably restricted diet, perhaps modern tree nuts are an option available to us today that most closely resembles a likely component of a diet eaten by our distant ancestors, and moreover, perhaps the nutrient profile of tree nuts (balance of macro-nutrients, content of fibre, presence micro-nutrients and low GL properties) closely reflects a good overall dietary balance?

  3. Anne 1 May 2009 at 7:04 pm #

    Thank you for this report which confirms my own experience.

    I eat at least 100 gram nuts and seeds per day and quite often more than that. Not as a replacement for fish, meat and eggs. I eat those too every day. This has been my eating pattern for appr. the last 8 years. I am slim and have excellent lab results. My weight rises immediately however if i start eating things like candy and croissants. I have learned this lesson time and again. Low GI carbs and lots and lots of nuts (without sugary or spicy ‘coats’ which is harder to find especially in petrolstations, railwayrestos etc) is what keeps me in shape, still at the age of 56.

  4. Kristine Franklin-Ross 1 May 2009 at 8:58 pm #

    I can understand eating veg year round as these seem to be available in some form or other even in winter, I can’t understand the fruit bit though. Surely this should only be eaten in season, this is how I ate it growing up in New Zealand. Our pancreas is not designed to deal with too much sugary food and diabetes is rampant today.

  5. sue 2 May 2009 at 2:01 am #

    would like just a littl more detail from Anne on quantities of meat, fish eggs each day. Am interested. Am nearly 65 and kept weight down for about 40 years pretty much low carbing, but love cheese and eat it. Very very satisfying for me. Stops my hunger. Lost most of my weight eating cheese 4o years ago!!!!

  6. Trinkwasser 2 May 2009 at 5:16 am #

    Satiety Index is a good explanation

    By eating more satiating foods one ends up eating significantly less calories overall. When I was shovelling dietician-approved carbs into my face my BG and insulin levels were swinging wildly and I was having constant carb cravings. Now I eat low carbs and more fats, protein and leafy greens as well as nuts, nut butters and cheese I can often go half a day without any desire for food (coffee doesn’t count, obviously!)

    The only downside of nuts, especially pseudo-nuts like peanuts or cashews, is the winds. Almonds are quieter.

    A friend

    tells a tale of some people who lost significant amounts of weight eating a high avocado diet. My dietician freaked over avocados “all that fat!” yet just like nuts (which she also freaked over for the same reason) they keep you fuller for longer without the insulin spikes which drive leptin etc.

  7. Dougal McGuire 2 May 2009 at 5:27 am #


    A one year intervention study (n>100) that is examining the effect of almond consumption on body weight and CVD risk factors that should be reporting in the near future…the last I heard the data was looking positive but it will be interesting to see the final results.

    The question that generally comes up (regarding nut consumption and abscence of body weight gain) is the mechanism(s) involved. Satiety is the big one but it really is not known why nuts are so satiating. It would be great to get to the bottom of that. The other mechanisms…GI, we wouldn’t agree on that so I will not go there! Energy expenditure/metabolism – conflicting results exist – Mattes (who you cited in your previous piece on nuts) published results showing a significant effect on energy expenditure…he has also published data showing no effect (difficult to explain unless you believe there are differences between peanuts and almonds which werer the test foods). Fat absorption…I love this – the amount of times you chew the nuts has an effect on fat absorption from almonds (also on hunger). However, this will only account for a small, but useful, amount of calories in the nuts.

    People have been surprisingly receptive to the idea that eating nuts does not lead to an increase in body weight. There is talk of the nut commodity groups seeking a FDA approved health claim in the US.

  8. Sue 2 May 2009 at 7:16 am #

    It seems to me that refined sugar is that baddie we should all be careful about – not fat which is the so called ‘baddie’ hyped by the food industry – with their reduced fat biscuits and cakes, so called healthy foods packed full of refined sugar. We see ‘reduced sugar’ products that are simply substituted with vast amounts of artificial sweeteners, so taste just as overwhelmingly sweet. Why can’t they make something that just has less sugar, or sweetener, so our tastebuds can adapt to less sweet foods. When baking I always reduce the sugar content and include wholemeal flour or bran to help improve the recipe.

  9. Linda 2 May 2009 at 7:46 pm #

    Sue, how I agree with you! Whenever I make a cake (very rarely for birthdays) I add half or under half the sugar it says and it still tastes fine to me and no-one comments on it. You don’t need to add sugar to pastry for a dessert tart either. People have got insensitive to high levels of sugar. Nothing really needs sugar added to it. You should just get used to the natural sugar content and not add any more. Why can’t they sell flapjack bars with no added sugar – just oats, nuts and dried fruit – scrumptious!

  10. Trinkwasser 2 May 2009 at 9:59 pm #

    To a degree you’re right about the sugar, but my glucometer tells me that starch is even more harmful mainly because the quantities are far higher. Dietary fats are only harmful in the combination with high quantities of carbs. It’s all interractive. Different nuts contain different micronutrients and different types of fats, maybe combinations eg. almonds and walnuts, would prove even more beneficial.

  11. Chris 2 May 2009 at 10:05 pm #

    Hi John, the notion of a seasonal metabolic shift and Vitamin D as a possible co-factor was touched upon recently in;
    Vitamin D would look to be a likely candidate; in time I expect more light will be cast upon vitamin D as having a part in seasonal regulatory governance.

    In ‘True You Diet’ you cast light upon evolutionary dietary precedent and apply that as to how people can fine tune their dietary habits to suit their own metabolic type. Once familiar with the importance of the diet of our ancestors it is not difficult to accept that evolution determines that the diet of our ancestors should have some relevance to our health today.
    But what of seasonality and of possible seasonal metabolic variation?

    I am just thinking out loud, there are potential dynamics to this that will take me a while to explore, nonetheless I wonder if this is an interesting line of thought? Here goes.
    In pre-history, and in any given habitat capable of supplying a varied diet, there would be seasonal variation to the variety and type of plant foods available to gatherers. In spring, lush and tender green leaves would be abundant, heading into summer, pithy stalks and unripe fruits may be possible food sources while perhaps some green leaves become either unpalatable of indigestible, late summer and into autumn ripe fruits become abundant. Later in autumn and through winter, tree nuts might become plentiful.
    Arguably, not so relevant to 21st century humans, but seasonal metabolic shift would have been helpfu in past timesl. The ability to keep warm and last out possible seasonal food scarcity would be important.
    Natures garden supplies an abundance of simple carbohydrate through the plentiful ripe fruits of late summer which the human body readily converts to adipose (fatty) tissue. The body lays down seasonal fat reserves ready for the coming winter. We might wonder if the body should conserve calories through the winter by a slowing of metabolism, but in fact the body must work harder to stay warm. Might the metabolism be ‘stoked up’ to better burn calories consumed complemented by those extra calories laid down in late summer as body fat? Compared to the preceding seasonally available foods tree nuts would be the least perishable, potentially still being available in early spring.

    In conclusion, could it be that dietary composition itself can regulate human metabolism according to the balance of constituent macro-nutrients and perhaps involving the presence of important co-factors, and are these interesting studies involving nuts suggestive that seasonal metabolic dynamism was important to our distant ancestors over hundreds of thousands of years?

  12. Chris 7 May 2009 at 10:49 am #

    Nuts can be expensive to buy in the prominent supermarkets. 1kg bags of almonds from an ethnic supermarket work out cheaper. I must look to see if better value is available online.
    ‘Am actually munching on almonds now. On the packaging is declared:-
    100g Provides Energy 579Cal (kcal)
    25.8g Protein
    20.7g Carbohydrates
    of which sugars 3.9g
    43.7g Fat
    of which saturates 8.5g
    8.3g Fibre
    and finally Sodium <0.05g


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