Dr. Steven Gundry on Lectins, Sweeteners and Fats: A Fair Check
Last reviewed October 18, 2026 · Part of our series What health influencers get right and wrong
In plain words: Dr. Gundry gets some things right: trans fats belong on a "No" list, high-purity stevia is a reasonable sweetener, and he's right to question some artificial sweeteners. But his central lectin claim holds only for raw beans, the idea that sweeteners are "just as bad as sugar" isn't supported, and his lectin advice appears on pages that sell supplements.
Who is Dr. Steven Gundry?
Dr. Steven Gundry is a former cardiac surgeon, author of The Plant Paradox, and founder of GundryMD, which sells supplements and foods. His food lists sort ingredients into "Yes" and "No."
How we checked
We collected claims from this person's own website, podcast transcripts or show pages, and checked each quote at the source in October 2026. When we couldn't find a claim in their own words, we left it out or say so. Then we compared each claim with human studies, large reviews and the positions of food-safety agencies like the FDA and the European Food Safety Authority (EFSA). We grade the claim, never the person. Many popular voices mix good advice with ideas that go further than the evidence, and that's true here too.
Claim by claim
| What Dr. Gundry says | Our verdict | Read more |
|---|---|---|
| Lectins cause leaky gut, inflammation and weight gain; avoid grains, nightshades and beans unless pressure-cooked (lectin guide) | Not supported | Lectins |
| Artificial sweeteners kill good gut bacteria, let bad ones thrive and encourage weight gain (sucralose) | Partly supported | Sucralose (Splenda) |
| Artificial sweeteners, including aspartame, encourage weight gain | Not supported | Aspartame |
| Artificial sweeteners "can be just as bad for your health as sugar" | Not supported | Sugars and sweeteners |
| Acesulfame-K and saccharin are on the "No" list | Partly supported | Acesulfame Potassium (Ace-K) |
| Stevia is on the "Yes" list | Supported | Stevia (Steviol Glycosides) |
| Monk fruit is on the "Yes" list | Partly supported | Monk Fruit Extract |
| Xylitol is on the "Yes" list | Partly supported | Xylitol |
| MCT oil and coconut oil are on the "Yes" list | Partly supported | Coconut Oil |
| Partially hydrogenated oils are on the "No" list | Supported | Partially Hydrogenated Oils (Trans Fat) |
| Herbicides like glyphosate "unleash genetic programs... turning genes on or off" | Not supported | Glyphosate Residues |
Where Dr. Gundry gets it right
- Trans fats. Partially hydrogenated oils clearly raise heart risk.1
- Raw beans. Raw kidney-bean lectins really can make you sick; cooking destroys them.2
- Questioning sweeteners. Some artificial sweeteners do change gut bacteria in studies, which is a fair concern (see Sucralose (Splenda)).
- Stevia. High-purity stevia has a solid safety record.
Where the evidence points another way
- Lectins in cooked foods. A review found no strong evidence from human trials that lectins in cooked whole foods are harmful.3 Beans, whole grains and tomatoes are linked with good health. His weight-gain evidence is his own patient observations.
- "Just as bad as sugar." Swapping sugar for sweeteners isn't proven to be equally harmful; see our Sugars and sweeteners guide for the mixed evidence.
- Glyphosate and genes. His page cites an advocacy report and a 2009 magazine article. We found no human evidence that food residues harm people.
- Coconut oil. It raises LDL cholesterol more than nontropical vegetable oils.4
Good to know
- His lectin guide page sells "Lectin Shield" capsules. That doesn't make a claim wrong, but it's worth knowing.
- Xylitol is on his "Yes" list, but a 2024 study linked higher blood xylitol to heart events, and it's extremely poisonous to dogs. See Xylitol.
- He promotes guar gum as a prebiotic fiber. Regulators found no safety concern for guar gum in the general population; see Guar Gum.
The takeaway for families
Keep the good parts: skip partially hydrogenated oils, cook beans thoroughly, and stevia is fine. But there's no need to cut cooked beans, whole grains or tomatoes, and you don't need a supplement to "block" lectins.
Frequently asked questions
Are lectins bad for you, as Dr. Gundry says?
Only in raw or undercooked beans. Cooked beans, whole grains and vegetables are healthy for most people.
Are artificial sweeteners as bad as sugar?
That's not supported. The evidence on sweeteners is mixed, but it doesn't show they're equally harmful.
Is Dr. Gundry right about trans fats?
Yes. Partially hydrogenated oils clearly raise heart disease risk and are banned in US food.
Sources
- Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies. BMJ (Clinical research ed.), 2015. PubMed 26268692 · doi:10.1136/bmj.h3978
- Phaseolus vulgaris lectins: A systematic review of characteristics and health implications. Crit Rev Food Sci Nutr, 2018. PubMed 26479307 · doi:10.1080/10408398.2015.1096234
- Is There Such a Thing as "Anti-Nutrients"? A Narrative Review of Perceived Problematic Plant Compounds. Nutrients, 2020. PubMed 32987890 · doi:10.3390/nu12102929
- The Effect of Coconut Oil Consumption on Cardiovascular Risk Factors: A Systematic Review and Meta-Analysis of Clinical Trials. Circulation, 2020. PubMed 31928080 · doi:10.1161/CIRCULATIONAHA.119.043052
This guide is for general education. It is not medical advice and does not replace advice from your doctor, pediatrician, allergist or registered dietitian. If you think you or your child reacted to a food, talk to a health professional. Research changes; we review these pages when new evidence or rules come out. Last reviewed October 18, 2026. Spotted an error? Email [email protected].