Update 12/6/20. Yacon syrup is the latest superfood to hit the market with the promise of helping people lose weight. Dr. Oz, who featured yacon on his TV show, even asked the tantalizing question, “Could this be the weight loss game-changer you've been looking for?” It turns out there is some research on yacon, and that will be the focus of this review. In addition, I'll also look at the study Dr. Oz did on yacon and try to give an idea of who should not use it. I admit that I didn’t know about yacon syrup until it was brought to my attention by my niece, Lori—so I want to say thanks to her for the heads up on this.
What Is Yacon Syrup?
Yacon syrup (say Ya-cone) comes from the roots of the yacon tree which grows in the Andes Mountains of South America. The tubers, which jut out from the roots of the tree, look like sweet potatoes. These tubers are a source of the soluble fiber, inulin, which in turn provides fructooligosaccharides (FOS). The scientific name for this plant is Smallanthus sonchifolius. Other names include Polymnia sonchifolia and Bolivian Sunroot.
How Does Yacon Syrup Work?
Yacon contains molecules called fructo-oligo-saccharides (pronounced, fruk-toe-oly-go-sack-a-rides) – or FOS. While it sounds complicated, FOS are basically just small sugar molecules. They are a type of fiber and found in many fruits and vegetables. As the name implies, FOS are composed of fructose although it doesn't have the same netegive effects as high fructose corn syrup.
We don't digest these FOS sugars very well. As such, FOS has fewer calories than regular sugar.
Because Fructooligosaccharides are a type of fiber, this also makes them a prebiotic. Prebiotics are the food of your gut microbiome. As such, one other effect is yacon syrup may improve your gut health. It’s thought that the fructooligosaccharides are at the center of the weight loss effects of yacon syrup. FOS sugars are derived from fructose. As such, foods (like fruits and vegetables) that have fructose also contain FOS.
Foods containing FOS include onions, bananas, and garlic. Yacon is said to have the most FOS. The soluble fiber, inulin is another example of FOS.
Foods With FOS
These dietary fibers are found in many foods. Food sources of Fructooligosaccharides include:
- Yacon
- Inulin (chicory root extract)
- Garlic
- Onions
- asparagus
and many others. It's possible FOS derived from different foods may have different effects.
Does Yacon Syrup Help Weight Loss?
Let's look at the research.
Study 1
In this investigation, 35 overweight women with high cholesterol were split into two groups:
- The women were divided into 3 groups:
- a placebo group (group 1)
- group 2 received 0.14 grams of yacon
- group 3 took 0.29 grams of yacon
- The study lasted 4 months
The women were advised to take the yacon 1 hour before meals.
Study Results
Compared to the placebo, women taking yacon syrup saw the following benefits:
- They lost an average of about 34 pounds and about 4 inches off their waist.
- Their Body Mass Index (BMI) significantly decreased.
- No rise in blood sugar levels. That's good.
- Insulin sensitivity improved (their insulin worked better)
- Significant reductions in LDL bad cholesterol
- Better bathroom frequency (3.5x better)
- There were no changes in triglyceride levels or total cholesterol or HDL levels (good cholesterol).
Study 2
This investigation found that 8.74 grams of FOS per day improved satiety (feelings of fullness) in people who used it. If yacon increases feelings of fullness it may reduce food intake. In theory, this may lead to weight loss.
Study 3
In this study, researchers gave diabetic rats were fed 3 different foods:
- Smallanthus sonchifolius (yacon)
- Ipomoea batatas (sweet potato)
- Agaricus blazei (a type of mushroom)
They observed that yacon did not lower blood sugar, hemoglobin A1C (a marker for diabetes), insulin levels, or reduce body weight. Ironically, both Ipomoea batatas and Agaricus blazei were shown to help diabetes in these rats.
Study 4
Not all studies show it works. In this investigation, 40 people overweight and normal-weight women were given 40 grams of yacon syrup at breakfast. The syrup contained 14 g of fructooligosaccharides (FOS). Here, women reported no changes in hunger, satiety or feelings of fullness after using yacon. Likewise, no changes in the hunger hormone, ghrelin was seen either.
The Dr. Oz Yacon Syrup Experiment
Yacon became popular when it was featured on the Dr. Oz show. Here's a summary of the study Dr. Oz discussed on his TV Show:
- The study lasted 28 days and involved 60 women. The women took a teaspoon of yacon syrup 3x a day before breakfast, lunch, and dinner.
- The women did not alter their diet or exercise programs.
The Results
- 40 of 60 women completed the study
- The women lost an average of 2.9 lbs
- Women lost an average of 1.9 inches from their waists
- 73% lost weight (that is, 29 women out of the 40 who completed the study)
- 68% said they would recommend yacon syrup (that is, 27 out of 40 women who completed the study)
While this was not a peer-reviewed study, it's interesting that some women did lose weight. Here is some of the good and bad about the Dr. Oz experiment:
The Good:
- The women lost weight, inches, and BMI
- The women were told to eat and exercise as they normally would. In theory, this means the only thing the women did was take yacon syrup. This could lend evidence that yacon had a real effect.
The Not-So-Good:
- There was no placebo group so compare the results to
- 20 of the 60 women dropped out of the study. That's a 30% drop-out rate. That's odd since the study didn’t seem to be hard to do.
- The study only contained women. What about men?
- Dr. Oz said 73% of women lost weight. This also means 29% of women did not lose weight with yacon syrup.
One pitfall to the Dr. Oz study was that the women knew that this experiment was for the Dr. Oz Show. This is significant because women LOVE Dr. Oz. They love him to pieces! Because of this, it's possible that the women may have worked harder at losing weight―even though they were told not to―because they knew they might be on TV and didn’t want to disappoint Dr. Oz.
I think the Dr. Oz experiment adds to the discussion because there isn't much yacon research out there. They showed some modest weight loss in a relatively short period of time. Losing about 3 pounds in a month is in line with guidelines for healthy weight loss.
The Woman's World Study
The February 17th, 2014 issue of Woman's World magazine (page 18) also had a story about yacon syrup. They conducted their own experiment where they had readers (they didn't say how many people) eat a 1500 calorie per day diet along with a teaspoon of yacon syrup before each meal. They said the people – presumably only women – lost 8 pounds in 7 days.
While I can applaud their efforts, this was not the best study because there was no placebo group and most healthy people will lose weight just by eating 1500 calories per day. Therefore, it's hard to say what caused the 8 pounds of weight loss – the yacon syrup or the 1500 calorie per day diet?
Can Yacon Syrup Raise Testosterone?
if you have heard yacon syrup can help men with Low T, the reason maybe because of this study, where rats were given extracts of yacon tubers and leaves. Researchers noted that yacon tubers increased not only sperm count but also testosterone levels.
This would make an interesting research topic for any college students reading this (hint, hint…).
Yacon Syrup Side Effects
For healthy people with no medical issues, yacon syrup is probably safe. Reported side effects from taking too much of the syrup include:
- diarrhea
- abdominal bloating
- nausea
- cramping
- gas
For those who are constipated, the syrup appears to help some go to the bathroom more regularly; however, for those who have diarrhea, it might make things worse.
- Remember, yacon syrup has fiber, so too much too soon might send you to the bathroom.
- People with irritable bowel syndrome (IBS) should be careful with yacon as its FOS content may have an effect on symptoms.
- There is at least one report of anaphylaxis. Anaphylaxis is a severe life-threatening allergic reaction. To be safe, if your allergic, avoid this supplement.
- One person – in the comments – stated the syrup lowered HDL (good cholesterol) and raised LDL (bad cholesterol) levels. Research has not shown this effect to occur. See the bergamot review for another cholesterol-lowering supplement.
- Yacon may reduce the absorption of some minerals (like iron).
- Since FOS are derived from fructose and since fructose can raise triglyceride levels (fats in the blood), some may wonder if yacon syrup raises triglycerides? So far this has not been observed. Animal and human studies appear to show yacon reduces triglycerides.
When picking a supplement, until more is known, make sure that it does not contain yacon leaves or extracts of the leaves, which may be toxic. The supplement should only contain the syrup derived from the roots of the plant.
How Much Works?
If you saw the Dr. Oz segment on TV (the video has been removed from his website), he recommended 1 teaspoon before or with each meal. That's 3 teaspoons a day for most of us. While that sounds appropriate to me, I'd say be more conservative, and try only 1–2 teaspoons per day for the first week, just to see what happens, before ramping it up to 3 teaspoons per day (we are all different, after all).
After you are using it 3 times a day, try experimenting with taking it 30–60 minutes before you eat to see if that helps it work better―and let me know. I'm curious.
Which Brand Is Best?
No studies highlight any brand as being better than others. That said if its going to work, the supplement only needs to contain yacon and nothing else.
While I have not tasted yacon syrup at the time of writing this review, one audience member of the Dr. Oz show called it “candy in a bottle”—which says to me it probably tastes pretty good.
Does Yacon Syrup Work?
So far two human studies seem to show yacon syrup helps improve satiety and weight loss This is encouraging although I'd like to see a few more studies. On the plus side, Yacon syrup FOS are is not expensive. Based on its price point and lack of side effects it may be worth taking a look at. If it works, it may take a few months to see a change.
Here are all the brands on Amazon