In fact, berries in general are, though moderation is certainly still important. If you found this page inadvertently wondering about raspberry ketones, we’ll be covering those on this page too for your convenience despite their lack of relation to the keto diet (jump to raspberry ketones).
Quick Answer: Raspberries are fine on the keto diet in moderation. A single raspberry is roughly .1 net carbs, so for every ten raspberries you eat, it’s about 1 net carb. This applies to both fresh and frozen berries (unsweetened), but not dried.
What’s in a Raspberry?
Fresh raspberries are 86 percent water, 12 percent carbs, 1 percent protein, and 1 percent fat. They are an excellent source of vitamin C, manganese, and fiber.
Raspberries: Keto Positive Points
-High in fiber
Raspberries rank among the highest whole food sources of fiber in the world with just over half their carb content coming from fiber. Fiber is particularly helpful while in the keto diet, because it can help alleviate constipation and diarrhea.
While not everyone suffers from either while on keto, both are common complaints. In the case of constipation, fiber speeds the passage of food through your digestive tract and adds bulk. In the case of diarrhea, it attracts and gels excess water content helping to firm things back up. Fiber also slows the digestion of carbs leading to a less severe glycemic response and makes you feel full faster, reducing your appetite.
-May help balance insulin levels
Several studies completed between 2010 and 2013 (study 1, 2, and 3) have found that raspberries (and other berries) not only slow glucose digestion resulting in more stable blood sugar levels, but they also reduce the amount of insulin necessary to process sugars. One study, however, showed this only to be true with liquid-based foods, such as juice. This suggests berries may help prevent insulin resistance while avoiding blood sugar spikes, particularly in things like smoothies.
-Low glycemic index
The glycemic index of raspberries seems to be a bit of a mystery. No reputable sources can give you a solid number, simply that the glycemic index is “low,” indicating it’s below 40. Note that even this is only found in mention within unrelated studies, such as this one and this one.
The University of Sydney, a leading authority on the glycemic index, states on their FAQ page that the lack of data for raspberries is due to the fact raspberries, “…contain…so little [carbohydrate] that their GI cannot be tested according to the standard methodology…Essentially, … eaten alone, [raspberries] won’t have much effect on your blood glucose levels.”
Raspberries: Keto Negative Points
-Infection and contamination risk
Due to the low level of processing and difficulty in cleaning more delicate berries such as raspberries, they have a slightly higher risk of contamination. Norovirus and Salmonella outbreaks are semi-common from berry sources as a result. Additionally, raspberries ranked 23rd in 2018 in a list of foods with the highest pesticide contamination rate based on data from the USDA’s Pesticide Data program.
You can reduce this risk by knowing the source of your berries and the food safety protocols followed in their production and harvest (a great reason to buy or pick local). It’s also recommend you thoroughly rinse raspberries right before consumption.
What are raspberry ketones?
Raspberry ketones are a chemical found in raspberries that give the berries their scent. They are, however, also found in other foods such as rhubarb, kiwifruit, peaches, grapes, apples, other berries, and more.
Prior to around 2002, the most common use for raspberry ketones was flavoring. These days though, thanks to a lot of marketing hype and a few very high-dose studies done on rats, they’re known more for their weight loss effects.
Unfortunately, the raspberry ketone weight-loss craze is mostly hype. Studies to date on raspberry ketones alone have all been on rats or rat cells.
2005- A study by the Department of Medical Biochemistry of the Ehime University School of Medicine in Japan found that mice fed a high-fat diet gained 10 percent less when that diet also included raspberry ketones.
2010- The Nutrition & Functional Food Research Team of the Korea Food & Drug Administration treated white fat cells with raspberry ketones and noted increased adiponectin levels (a hormone tied to blood sugar and metabolism regulation).
2012- Following the 2010 study, the College of Food at Shenyang Agricultural University in China found that rats fed raspberry ketones had higher adiponectin levels as well.
2017- Researchers from the Department of Human Sciences at the College at Ohio State University fed rats that were already overweight raspberry ketones, and found they ate less as compared to the control group. However, the difference was minimal.
All of these studies involved very high doses of raspberry ketones. In fact, to reach the levels administered you would have to take around 100 times the recommended daily dosage.
The only human study involving raspberry ketones was done in 2013 by the Center for Applied Health Sciences in Ohio. It involved a composite supplement which also included caffeine, garlic, capsaicin, ginger, and synephrine. Those on the supplement lost 5 percent more weight than those who were not.
To date, the Natural Medicines Comprehensive Database lists evidence for raspberry ketones and weight loss as “insufficient.”
More surprisingly, the raspberry ketone levels found in actual raspberries are very low. To reach a single daily dose of raspberry ketones you would need to eat about 90 lbs of raspberries. The supplements marketed today are lab-made as a result.
What do raspberry ketones have to do with keto?
Finally, the inclusion of “ketone” in raspberry ketones frequent creates a point of confusion.
Ketones, as most people know them, are a fuel source produced by the breakdown of fat in times of low carbohydrate intake (read a more in-depth explanation here). They are the fuel source utilized while on the keto diet, but raspberry ketones have nothing to do with ketosis, ketone bodies, or the keto diet.
Note that said, “ketone bodies” that time, and not just ketones. That’s because ketones as just defined is actually a group of three ketones called ketone bodies.
The three ketones that make up ketone bodies aren’t the only type of ketones. The definition a ketone is actually,
“any of a class of organic compounds (such as acetone) characterized by a carbonyl group attached to two carbon atoms.”
As far as biological sources, ketones are also found in plants such as raspberries, hence the name. It is important to note, though, that raspberry ketones are not a form of exogenous ketones and can’t be used as a supplement for that purpose. They again, have no relation whatsoever to ketosis or the keto diet.
Still have questions about raspberries? Feel like we missed something? Drop us a comment!