Nuts Don’t Cause Expected Weight Gain

Nuts Don't Cause Expected Weight Gain
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Nuts are packed with nutrition, but they are also packed with calories. Why, then, don’t nuts seem to make people fat?  In my video Nuts and Obesity: The Weight of Evidence, I profile a review published back in 2007 looking at about 20 clinical trials that had been done on nuts and weight. Not a single one showed the weight gain one would expect.

All of the studies either showed less weight gain than predicted, no weight gain at all, or actual weight loss—even after study subjects added a handful or two of nuts per day to their diet. However, the studies lasted just a few weeks or months. What about long-term?

Maybe in the short run nuts don’t lead to weight gain as much as other foods, but what about after years of eating nuts? Well that’s been examined six different ways in studies lasting up to eight years. One found no significant change and the other five out of six measures found significantly less weight gain and risk of abdominal obesity in those eating more nuts.

Since that review is now 5 years old, in my Weight of Evidence video I update it to include all of the studies published since, including a number published this year. For example, in 2012 there was study in which people added over a hundred pistachios to their daily diets for three months and didn’t gain a pound. How did 30,000 calories disappear?

What happened to the missing calories? The mystery has been solved. In my video series that started with Solving the Mystery of the Missing Calories, I presented the “pistachio principle” and the fecal excretion theory.  In my next video these theories were put to the test.  I then explored the Dietary Compensation Theory, and by the final video in the series we had figured it out.

Part of the trick seemed to be that nuts boost fat burning within the body. But how? It could have something to do with the amino acid arginine (see my 2-min. video Fat Burning via Arginine) or the phytonutrients found in nuts and green tea (Fat Burning via Flavonoids).

Since nut consumption has been associated with lower rates of heart disease and living a longer life we should include them in our regular diet without worrying that they’re going to make us fat.

Michael Greger, M.D.

PS: You can subscribe to my videos for free by clicking here.

Image credit: jypsygen / Flickr

  • Chris

    Does it matter what type of nut and were the nuts raw?

    • Marisa R.

      Yes, does it matter whether the nuts are raw or roasted? And what about salt? My dad eats packaged “mixed nuts” every day and my mom is convinced that they’re contributing to his weight gain.

  • http://www.facebook.com/yoshi10usa Yoshi Nakayama

    If you count calories, how can you explain that you will gain 50 gram of weight when you eat 10 gram of sugar candy? Conservation of mass in physics should exist. Counting calories is a myth. What do you think?

    • http://www.DonForresterMD.com/ Don Forrester MD

      The laws of physics do apply but “weight” loss or gain is complicated by a variety of factors. Calories are important but more important is calorie density. We tend to eat to satisfy our hunger which is calmed by stretch and fat receptors in stomach plus nutrients absorbed into body. Weight loss or gain can be due to changes in muscle mass, water, fecal material and/or fat. In working with patients at the McDougall clinic who are eating a low fat starch based diet I observe weight loss during their stay based on fat loss(less calories consumed while satisfying their hunger), water loss(less sodium intake) and faecal loss(due to increase in transit time). The best introduction to the concept of calorie density is the DVD by Jeff Novick, Calorie Density: Eat More, Weigh less and Live Longer. Doug Lisle’s presentation, How to lose weight without losing your mind” seen on you tube.. The laws of physics do apply but “weight” loss or gain is complicated by
      a variety of factors. Calories are important but more important is
      calorie density. We tend to eat to satisfy our hunger which is calmed by
      stretch and fat receptors in stomach plus nutrients absorbed into body.
      Weight loss or gain can be due to changes in muscle mass, water, fecal
      material and/or fat. In working with patients at the McDougall clinic
      who are eating a low fat starch based diet I observe weight loss during
      their stay based on fat loss(less calories consumed while satisfying
      their hunger), water loss(less sodium intake) and faecal loss(due to
      increase in transit time). Of course after leaving the program weight loss continues at about 1/2 to 2 pounds per week depending on exercise, where the patient started and how well they follow recommendations. The best introduction to the concept of
      calorie density is the DVD by Jeff Novick, Calorie Density: Eat More,
      Weigh less and Live Longer. Doug Lisle does an excellent job exploring the psychology and biology of losing weight in his two You Tube video’s, “How to Lose Weight without losing your Mind” and “The Pleasure Trap”(he coauthored a book by the same title)… both also available as DVD’s. The complexity of the nutritional science can be appreciated by viewing the 56 videos relating to obesity on Dr. Greger’s website. I would explain a weight gain of 50 grams with only the consumption of 10 grams of sugar as being related to some other factor and not violation of the laws of thermodynamics. Happy New Year.

  • http://www.facebook.com/arielgailmaclean Ariel Gail MacLean

    but what about fried nuts found most everywhere?

  • http://twitter.com/hkeye7 Jesper Ternstedt

    Fantastic source of knowledge. Thank you so much!

  • Good Luck Duck

    I am still confused about nuts and omega acid profiles. I read that almonds are preferable to peanuts, but their profiles seem similar.

  • Pingback: Using the Motivational Triad to Eat Healthier, Part 4: Energy Efficiency | Leading Effectively: Official Blog of the Center for Creative Leadership()

  • bob kerr

    How do i reconcile Esselstyn’s recommendations for no nuts or avocado for people with heart disease with the info on nut consumption.

  • Jorge Calvo

    I love eating raw non gmo cashew butter. But seriusly, I don’t understand paleo guys saying ohhh nooo, it’ll cause leptin resistance. Must be those lectins messing with our hormones. What a joke. Arnold Schwarzenegger even ate cashew butter to gain muscle mass. Cashews have a high dense protein amino content. (protein keeps you sated longer right?) Same goes for pistachios and walnuts(added benefit of higher omega 3 ratio)

    plz tell me if Im doing something wrong in my diet. Im a college student who relies on my tasty unsweetened natural nut butters. Their easy on the pockets too along with sprouted breads I use

    Nb : I’m getting a lot of misinformation about nuts, legumes, beans and sprouts causing leptin resistance. Especially the the talk of lectins bears in mind. And for the record I have a shitty metabolism and am super skinny now thanks to good protein dense carbs, nuts, legumes and cooking with virgin cocnut oil

  • Frederique Geubbels

    Amazing research! I really appreciate your dedication to make these incredibly interesting videos! I always use them to educate myself more and more about my plant-based-whole-food lifestyle! Thanks for your work Dr. Greger :)

    • Joseph Gonzales R.D.

      Thank YOU for watching!

  • Christina Karlhoff

    Hi there,

    Why is there such controversy surrounding the inclusion of nuts and seeds in a nutritious diet? For example, some experts insist that nuts and seeds should be left alone if weight loss is a goal…a sentiment that is held in various other experts eyes (cardiologists for example). Why is this so? Where is the final say?

  • Miroslav Kovar

    Dr. Greger, why don’t you mention that some of the studies mentioned in the video were funde by Australian Tree Nut Industry? Your biased, uncritical promotion of plant-based diet is really as misleading as meat industry sponsored propaganda.

    • Thea

      Miroslav: As part of the question and answer session of a live talk, Dr. Greger recently explained part of his process for evaluating studies. One of the steps Dr. Greger always does *first* when evaluating a study is to go straight to the bottom of the study and read who funded the study, which scientists worked on it, and any conflicts of interest. Based on that information, Dr. Greger can know to be especially critical if necessary as he reads through the study.

      So, rest assured, Dr. Greger pays close attention to this type of information and is very critical when called for. Just because a say chicken company funds a chicken study doesn’t mean that science is invalid. But it does mean that extra care needs to be paid to the details of the study and Dr. Greger knows that regardless of whether the origins come from animal or plant industries.

      Also, Dr. Greger does mention this type of information when he thinks it is relevant or of special note–even when promoting a plant-positive study. And finally, Dr. Greger gives us the references for the studies so that we can find any of those details if we want when the information is not specifically mentioned. Nothing is hidden from you.

      In short, while I understand your concern, I do not think it is warranted for the work on NutritionFacts.

  • disqus_pFomH2XM20

    This is very interesting, it fits in well with my own ideas on this subject. One has to ask if our warm blooded metabolism that has evolved over more than 100 million years could be such a flawed system that could cause us to starve to death if there were small food shortages? Suppose that some animal that normally eats 2000 Kcal a day and expends this much, now has to expend 50 Kcal more per day to get to its food and that the food that it then gets to eat is a bit less, say 50 Kcal less per day.

    Common sense would suggest that the animal will simply down-regulate its metabolism to balance its energy balance. How exactly this is implemented (e.g. fat signal to the hypothalamus their status via hormones they produce, if they are filled more or less on average is information that can be acted on), is not all that important. Evolution would have had to lead to some feedback mechanism via whatever biochemical pathways that could be utilized to allow the metabolic rate to match energy intake (within some limits, too large a shortfall obviously cannot be compensated for). A shortfall of 100 Kcal/day that isn’t compensated will lead to 1 kg weight loss every 80 days, so within a few years a human sized animal would face starvation.

    But if we assume that the metabolic rate will be adjusted to compensate for fluctuations in the energy intake, then this works in both directions. If we eat a bit more every day while keeping exercise levels the same, we should not gain weight on the long term. Of course, you may gain some weight initially, but then the fat cells get filled to a higher degree which changes their signaling to the hypothalamus, which will cause the metabolic rate to be increased a bit. But even that initial weigh gain may not last permanently. Suppose that you weighed 70 kg and ate 2000 kcal/day. Then later you started to eat 2100 Kcal and that caused your weigh to increase to 71 kg. In the initial state there was a dynamical equilibrium of energy intake and energy expenses at that 2000 Kcal, while in the final state you have reached equilibrium at 2100 Kcal. The question you have to ask is why you can’t reach that same dynamical equilibrium at 2100 kcal at your original weight of 70 kg?

    A few relevant factors are that at 71 kg you are probably expending more energy due to having to carry 1 kg extra with you during physical activities. Also the extra 1 kg of body tissue will have some metabolic activity. But there will also have been an increase in the overall basal metabolic rate that isn’t just due to the metabolic activity of the extra 1 kg. If we were to disregard this latter contribution the body gain would have had to be a lot more (fat tissue burns 4.5 kcal/(kg day) ,so 100 Kcal more energy intake would lead to 22 kg weight gain is we ignore active feedback mechanisms).

    Now, increasing the metabolic rate means that the body will have to use more nutrients. The body will also try to maintain a dynamical equilibrium between the intake of essential nutrients and the use of these nutrients. And if this is perturbed, the body will use feedback mechanisms to attempt to restore dynamical equilibrium. This means that if you add nutrient poor calories to your diet then the feedback mechanisms that work to keep your body weight stable will be compromised by the feedback mechanisms that are aimed at maintaining proper body stores of essential nutrients, the latter will feed back on the former and reduce the increase in the basal metabolic rate. Your weight will then increase more and be determined by the energy it takes to carry your weight along and by the metabolism of the extra fat tissue.

    However, something does not seem to add up here: You now reach a dynamical equilibrium w.r.t. the energy balance while that should be incompatible with dynamical equilibrium of the other essential nutrients if we eat more junk food! The solution to this paradox is to take into account that the body can compromise on the use of nutrients involved in metabolism, e.g. it has the option of using less anti-oxidants. So, at the end of the day you will reach a dynamical equilibrium w.r.t. to both the nutrient and calorie intake, but the more unhealthy the extra food is you eat, the less healthy the increased metabolism will be for you.