Do Raspberry Ketones Burn Fat?

fresh raspberriesEver since Dr. Oz claimed that raspberry ketones were “fat burners in a bottle” we’ve had lots of fans ask: “Do raspberry ketones burn fat?”

While TV is great for watching Homeland, sports, reality shows and Seinfeld reruns, it’s probably not the best place to get your nutrition or health information.  As the LA Times recently reported,….””Just because someone’s on TV, just because they’re wearing scrubs, doesn’t mean they’re an expert on nutrition,”  and ” getting your health information from TV, you might not be as well-informed — or as healthy — as you could be.”

Before you spend your hard earned money on Dr. Oz’s latest made-for-ratings, highly sensationalized “miracle fat burner,” here are five things you need to know about the fat-zapping ability of raspberry ketones.

Here’s how good TV equals bad medicine

1. No human studies show that raspberry ketones aid in weight loss or fat burning

Raspberry ketones are natural phenolic compounds in red raspberries that create the aroma of the berries. The only published scientific health research (there have been three studies to date) on raspberry ketones are considered preliminary because they are either animal model or laboratory studies. No studies have have been conduced with humans. Not one.

All three studies were conducted in Asia and published in small experimental publications rather than major medical journals. There was no disclosure by the researchers whether or not the supplement industry funded their studies, but one would expect that they were probably funded by the industry.

One study reported that feeding raspberry ketones to rodents resulted in increased secretion of adiponectin, a hormone secreted by fat cells that helps the body break down fat and plays a role in obesity and insulin resistance. In the other study, mice were fed a high-fat diet with varying amounts of raspberry ketones. The results showed that those with higher amounts of raspberry ketones were protected against fat gains and increased fat oxidation (burning). The third study exposed fat cells to raspberry ketones and found that the ketones were able to stimulate lipid metabolism by stimulating lipolysis, and the secretion of adiponectin in specific types of fat cells.

There’s a big difference between mice and humans and while the preliminary research is of interest, many more studies (including human studies) are necessary to make any type of claim that the products will help a human lose weight or increase fat burning.

raspberry ketones interview2. Dr. Oz’s raspberry ketone expert, Lisa Lynn, is not a weight loss expert

The other suspect part of the Dr. Oz segment about raspberry ketones is the so-called “expert,” who promoted the supplements. The segment features Lisa Lynn, who Dr. Oz referred to as a weight loss expert. However, Lisa Lynn has is not a dietitian, has no nutrition degree, is not a nurse or medical doctor. She does have certificates for exercise training from the International Sports Sciences Association and she sells raspberry ketone supplements on her website in the LynFit Accelorator supplement, which you can buy for $33.00 on her website. That doesn’t make her a “weight loss expert,” and certainly doesn’t qualify her to speak about the nutritional biochemistry of ketones and fat metabolism.

After hearing what she said on-air about the supplement, I knew immediately that she has no biochemistry or nutrition background:

Dr Oz: How did you find this? lynfit-raspberry-ketones

Lisa Lynn: Research, research, and research.

Lisa, where is the research. There are two published mice studies in the worldwide medical literature database. Where are you getting your “research?”

Lisa Lynn: They[raspberry ketones] help your body burn fat. They slice it [fat] up in the cells so it burns fat easier….”

From nutritional biochemistry, there is absolutely nothing that “chops up,” or “flushes” fat from the body. it’s just simplistic ludicrous statements mean to get people to buy into the promises of the product.

3. Raspberry ketone supplements provide more than raspberry ketones

The other problem with assuming that Raspberry Ketone supplements aid in weight loss is the fact that most of the products contain much more than raspberry ketones. They often contain green tea, hoodia (a known appetite suppressant), caffeine or capsaicin (compound that makes peppers hot.) All of these ingredients have more evidence to providing a weight loss benefit than raspberry ketones. I believe the supplement manufacturers do this intentionally so that they can hedge their bets with product that have every possible item to aid in weight loss in one supplement.

However, the impact of all these items together would result in small impacts on our body weight. WE can do much more to lose weight by eating raspberries and other healthy foods than by spending upwards of $25.00 per bottle of raspberry ketone supplements.

4. Manufacturers must *Asterick* their claims

After I watched the Dr. Oz raspberry ketone segment, I emailed and called several companies that manufacture and sell raspberry ketones nationally. I asked them all for any evidence to support their claims. Not one company returned my calls or emails and none provided any scientific evidence to support their claims. What’ more, with no efficacy studies, manufacturers have no basis for which to base any dosage amounts of raspberry ketone. That’s why every supplement lists different amounts of raspberry ketones as  a daily dosage.

Also, look at the small print on the bottles of the supplements, you’ll see an astericks by the fat-burning, metabolism-boosting claim, which reads:

This information has not been evaluated by the Food and Drug Administration, nor has it gone through the rigorous double-blind studies required before a particular product can be deemed truly beneficial or potentially dangerous and prescribed in the treatment of any condition or disease.

U.S. Food and Drug Administration

5. Weight loss supplements don’t have to deliver what they claim

This may be hard  to swallow, but the overwhelming scientific evidence shows that there is no shortcut to being fit, healthy or lean. Because the vitamin and supplement industry is not regulated by the US Food and Drug Administration (FDA), so supplements can be sold without showing that they actually deliver what they claim.

Bottom line: There are no magical fat burners…and if something sounds too good to be true, changes are it is…especially if you heard it on TV.

–Julie Upton, MS, RD, CSSD


  1. Valerie Boone says

    Wow, thanks for this great article. My mother and I were just having a “discussion” yesterday on Dr. Oz and how much of an “expert” he is on health and nutrition. I take everything he says with a grain of salt and do my own research.

  2. says

    I work in a grocery store (trader joes) and I can see the difference that Dr. Oz makes w/ his recommendations. I just sit there and listen and try to find the logic behind why these people are buying what he recommends. I hope the majority of people understand that his show is for entertainment purposes and are not recommendations to go out and eat raw meat (as one guest suggested),or take these pills for weight loss. Thanks for doing this.

  3. Eileen Harris says

    Dr. Oa swears by so many different things—green tea pills, Acai, Raspberry, Reservatol…..etc. etc. that I am beginning to think he is sponsored by the makers of these. Common sense and healthy eating of natural foods will work everytime.

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