Fat Burning via Flavonoids

Michael Greger M.D. FACLM · August 27, 2012 · Volume 10

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Flavonoid phytonutrients (found concentrated in citrus, berries, red onions, beans, green tea, grapes, and cocoa) may boost metabolism enough to significantly slim one’s waistline.

Discuss

Transcript

What accounts for the thermogenic effect of nuts—their purported ability to boost metabolism, such that one could potentially burn more fat just sleeping, or sitting around? An explanation for this rise of resting energy expenditure is not obvious. The Texas A&M folks thought it was the arginine, but, others recently suggested it may be a function of the flavonoid phytonutrients in nuts. Based on what kind of evidence? Studies like this.

“The Effects of Concord Grape Juice on Appetite, Diet, and Body Weight.” Just like nuts are calorically dense, yet don’t seem to cause weight gain, Welch’s was keeping their fingers crossed that the same would be found for purple grape juice.

They had people guzzle down two cups a day for three months. Now you got to understand, Welch’s grape juice has more sugar than Coca Cola. Two cups of purple grape juice contains the equivalent of 20 spoonfuls of sugar. The control group was basically given grape Kool-Aid—a “substitute grape-flavored drink.” Same number of calories; Same amount of sugar; but, just no detectable phytonutrients.

So, at two cups a day, they were giving hundreds of extra calories a day to these people. Surely, after three months, they’d gain a couple pounds. What do you think they found?

The grape-flavored sugar water group did, indeed, gain a significant amount of weight. How could they not, with all that extra added sugar in their diet? But the grape juice people didn’t. In fact, are you ready for this? Their waist circumference significantly shrunk. They appeared to burn away significantly more tummy fat—by drinking grape juice!

So, maybe there is something to the theory put forth by the nut and green tea people that flavonoid phytonutrients are capable of increasing “thermogenesis [heat generation] and fat oxidation.” If true, then it’s just one more reason to eat nuts, and drink green tea—not grape juice. Instead, eat Concord grapes.

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.

Please consider volunteering to help out on the site.

Sources

Acknowledgements

Images thanks to Todd Coleman; fortinbras; and Paul Goyette via flickr

Topics

What accounts for the thermogenic effect of nuts—their purported ability to boost metabolism, such that one could potentially burn more fat just sleeping, or sitting around? An explanation for this rise of resting energy expenditure is not obvious. The Texas A&M folks thought it was the arginine, but, others recently suggested it may be a function of the flavonoid phytonutrients in nuts. Based on what kind of evidence? Studies like this.

“The Effects of Concord Grape Juice on Appetite, Diet, and Body Weight.” Just like nuts are calorically dense, yet don’t seem to cause weight gain, Welch’s was keeping their fingers crossed that the same would be found for purple grape juice.

They had people guzzle down two cups a day for three months. Now you got to understand, Welch’s grape juice has more sugar than Coca Cola. Two cups of purple grape juice contains the equivalent of 20 spoonfuls of sugar. The control group was basically given grape Kool-Aid—a “substitute grape-flavored drink.” Same number of calories; Same amount of sugar; but, just no detectable phytonutrients.

So, at two cups a day, they were giving hundreds of extra calories a day to these people. Surely, after three months, they’d gain a couple pounds. What do you think they found?

The grape-flavored sugar water group did, indeed, gain a significant amount of weight. How could they not, with all that extra added sugar in their diet? But the grape juice people didn’t. In fact, are you ready for this? Their waist circumference significantly shrunk. They appeared to burn away significantly more tummy fat—by drinking grape juice!

So, maybe there is something to the theory put forth by the nut and green tea people that flavonoid phytonutrients are capable of increasing “thermogenesis [heat generation] and fat oxidation.” If true, then it’s just one more reason to eat nuts, and drink green tea—not grape juice. Instead, eat Concord grapes.

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.

Please consider volunteering to help out on the site.

Images thanks to Todd Coleman; fortinbras; and Paul Goyette via flickr

Doctor's Note

This completes my seven-part video series on this fascinating phenomenon. I began by reviewing the balance of evidence on why nuts don’t tend to contribute to weight gain in Nuts and Obesity: The Weight of Evidence. I then introduced two theories on Solving the Mystery of the Missing Calories, both of which were put to the test in a study on peanut butter, Testing the Pistachio Principle. Next came Testing the Dietary Compensation Theory, an elegant study using walnut smoothies, followed by the big reveal in Testing the Fat-Burning Theory. But why might nuts help you burn more fat? Arginine is one possibility (see Fat Burning Via Arginine), and today’s video on flavonoids presents another. For more on flavonoid phytonutrients, see Phytochemicals: The Nutrition Facts Missing From the Label. For a comparison between fruit juices, see Best Fruit Juice, along with a video on putting that knowledge into practice: Pink Juice with Green Foam. Which beverage has the most antioxidants, though? See Better Than Green Tea. And what about juiced vegetables, such as carrots and beets? See Benzene in Carrot Juice, and an entire series starting with Doping With Beet Juice. And for more on the wonders of Concord grapes (yum!), see Plant-Based Diets and Cellular Stress Defenses.

For additional context, be sure to check out my associated blog posts: Nuts Don’t Cause Expected Weight Gain; Is Caffeinated Tea Really Dehydrating?; Burning Fat With Flavonoids; Do Vegans Get More Cavities?; and Flax Seeds for Diabetes.

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