An elegant study is presented testing the appetite-suppressing effects of walnuts.
Maybe the reason why 90% of the relevant studies show no weight gain from nut consumption is that nuts are so satisfying, so satiating, so appetite suppressing that throughout the rest of the day--totally unconsciously, you just eat less. So if researchers add a handful of nuts to your daily diet totaling 200 calories and they were just so filling that it displaced 200 calories of something else you would have normally eaten then that could explain how one can remain in energy balance even though they just added a calorically dense food like nuts to their daily diet. And hey if you felt so satisfied you unintentionally ended up eating 250 calories less each day then that could explain why in a few of the nut studies people actually lost weight.
Recently they tested walnuts. “It has been proposed… mainly on the basis of observational studies, that nuts may provide superior satiation, may lead to reduced calorie consumption, but evidence from randomized, interventional studies is lacking.” Until now.
They double blinded the study by disguising the walnuts in a smoothie, “The walnut-containing liquid meal contained walnuts, frozen mango, frozen strawberries, banana, frozen berries, and pineapple juice.” Sounds good. Whereas the “placebo liquid meal contained oil, mango, strawberries, banana, berries, and juice, and 40 drops of walnut flavoring.” In fact they made it so you literally couldn’t tell the difference in blind taste tests. And they were made with the exact same number of calories, so if there was nothing special about nuts then you should feel just as satiated either way, but no, after a few days on the placebo, the walnut flavored smoothie people just felt something was missing. Everyone drank their smoothies at breakfast, and right before lunch the folks that didn't get the real nuts felt significantly less full, less satiated even after the no chewing and full fat absorption.
So you can see how if you had nuts for breakfast you may very well unintentionally eat a smaller lunch than you otherwise would, and so in this way nuts could actually decrease daily caloric consumption.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Kerry Skinner.
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This is the fourth of a seven-video series on the fascinating phenomenon of Solving the Mystery of the Missing Calories—why don't nuts make us fat? I review the balance of evidence in Nuts and Obesity: The Weight of Evidence and introduced two theories on Monday, both of which were not well supported by a study on peanut butter I detailed in yesterday's video-of-the-dayTesting the Pistachio Principle. We finally seem to be getting somewhere, though we still haven't accounted for all the missing calories. Tomorrow we'll check out the Testing the Fat Burning Theory. For my crazy breakfast smoothie concoction see A Better Breakfast, and if you haven't yet, please feel free to subscribe to my videos for free by clicking here.