Do raspberry ketones really work? Can they help you lose weight, and, most importantly, are they safe? It seems that there’s always some new supplement on the market that claims to help with weight loss. Unfortunately, most of them turn out to be either ineffective or downright dangerous. Raspberry ketones have been on the tip of many people’s tongue since Dr. Oz mentioned it on his talk show as a “fat-burner.” Do raspberry ketones really live up to their weight loss promise?
What Are Raspberry Ketones?
Raspberry ketones are found naturally in a number of fruits and berries, not just raspberries. In fact, raspberries aren’t as high in raspberry ketones as some other fruits. Other natural sources of raspberry ketones are cranberries, blackberries, apples, grapes, peaches and the bark of some trees. It’s used in the cosmetics industry for its fruity fragrance and as a food additive. Because natural raspberry ketones are available naturally in limited supply, the raspberry ketones in weight loss supplements are usually made synthetically. Otherwise, you’d pay a pretty steep price for a bottle.
Do raspberry ketones really work for weight loss? Unfortunately, there’s still no credible human research looking at the effects of raspberry ketones for body weight. A study carried out in mice showed mice that got raspberry ketones in their diet and ate a high-fat diet were protected against weight gain, although a prior study in rodents failed to show the same benefits.
How Might Raspberry Ketones Boost Fat Loss?
It seems to work by increasing the amount of adiponectin fat cells release. Adiponectin is a hormone produced by fat cells that boosts fat breakdown by subtly boosting your metabolism. Adiponectin also has favorable effects on glucose metabolism. Fat cells normally produce adiponectin, and thinner people appear to produce more than people who are overweight or obese.
In structure, raspberry ketones are similar to capsaicin, a chemical in hot chili peppers that has metabolism-boosting benefits according to some research. What’s concerning is raspberry ketones are also structurally similar to synephrine, an ingredient in some weight loss products that acts as a stimulant. Synephrine has been linked with irregular heart rhythms and blood pressure elevations. Not surprisingly, there are concerns about its safety. Whether this also applies to raspberry ketones isn’t clear. Despite this, most sources will tell you raspberry ketones have no real side effects. That’s not necessarily true. No one knows about the long-term safety of taking raspberry ketones to lose weight, but because the fact that they’re structurally similar to synephrine is of concern.
Why People on the Dr. Oz Show Who Have Taken Raspberry Ketones Lose Weight
On this show, Dr. Oz showed before and after photos of people who have taken raspberry ketones and had lost significant amounts of weight. If you’ll look at some of these photos, you’ll see some of the people in the after shots were photographed holding weights or while working out. Did they lose weight from raspberry ketones or because they started a workout program? Even Dr. Oz points out the importance of using raspberry ketones in conjunction with diet and exercise. Even if human research ultimately shows raspberry ketones have weight loss benefits, it’s unlikely to be a “magic pill” that lets you eat what you want to eat and lose weight without exercising.
The Bottom Line?
Don’t completely dismiss raspberry ketones for weight loss. They may have benefits but there’s still not enough research to say whether they really work. Your best approach for losing weight? Cut back on processed foods. Replace them with more fiber-rich fruits and vegetables to fill up without adding lots of calories. Stop drinking your calories. Skip the soft drinks and sip unsweetened green tea. Just as importantly, do at least 20 minutes of exercise a day, strength and resistance training, and make an effort to move around more during the day. These may be common sense, but they work.
Planta Med 2010;76:1654-8.
WebMD. “Raspberry Ketone”
Medscape.com. “Is Raspberry Ketone Effective for Weight Loss?”