Episode check · Lifestyle and genes
Heart risk climbs from a fasting blood sugar inside the normal range, the episode says. Four of seven studies disagree.
We checked six claims from a 45-minute episode on insulin resistance against 62 studies. Four of seven studies disagree with the lead, that heart attack and stroke risk climbs once fasting blood sugar passes the level said on the episode. The biggest, a pooled analysis of 102 studies, found no clear link across the normal range. The study the episode points to measured diabetes, not heart disease. One claim has strong support: insulin goes up before blood sugar, and many people with normal blood sugar already have high insulin. The studies lean toward the other four, with limits. Only one small study, of 3 men, found people off insulin within days. No study tested the exact lines said for fasting insulin or A1C. A walk after meals lowers the spike, though most studies tested longer or repeated walks. The chapters we did not check are in grey.
“Why Your Insulin Resistance Isn't Permanent (And How to Fix It)”
16 chapters · 6 claims checked against 62 studies · 8 chapters not checked yet · checked Oct 27, 2026 Watch on YouTube →
Reversing Insulin Resistance and Introduction to Blood Sugar
“I I've taken people who are type two diabetics, who are on insulin for ten years, who are so sick and massively overweight. And within three days, they're off the insulin.”
Mark Hyman, solo episode.
What 9 studies found
1 agree · 8 partly agree
Only one of nine studies agrees, and it followed 3 men: they stopped insulin after 5 to 18 days of fasting. Eight are mixed. In larger trials, people came off insulin over weeks or months, not days: 39.4% at 12 months in one trial, and 31 of 78 in another. Others cut their dose rather than stopping.
Computed from 9 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
Every study and its exact words“In three months, they're completely normal blood sugar.”
What 9 studies found
2 agree · 7 partly agree
Two of nine studies agree. In 11 people who had had diabetes for under 4 years, fasting blood sugar fell to normal after 1 week of a very low-calorie diet. In a small trial, more people on a low-carb diet got their A1C below 6.5% by 16 weeks. Seven are mixed: A1C fell, but most people stayed in the diabetes range or kept taking diabetes drugs.
Computed from 9 studies that test this point, each judged by two readers, in full. 9 more studies are waiting for a full read and do not count yet.
Every study and its exact wordsWhat is Blood Sugar and How Insulin Works Lead finding
“Because your blood sugar is the last thing to go up when you're in a metabolic dysfunction. It's the last thing to go up. The first thing up is your your insulin.”
Mark Hyman, solo episode.
What 5 studies found
3 agree · 2 partly agree
Three studies agree and two are mixed. In 515 Israeli adults with normal blood sugar, fasting insulin was the strongest sign of who got type 2 diabetes over 24 years. In British civil servants, insulin output rose up to 7 years before diagnosis. In the two mixed studies, from Britain and Denmark, people who later got diabetes already had higher blood sugar and higher insulin when first tested, as early as 13 years before diagnosis. So those studies cannot say which rose first.
Computed from 5 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
Every study and its exact words“They have severe insulin resistance, and they have high levels of insulin while their blood sugar may be normal.”
What 5 studies found
3 agree · 2 partly agree
Three studies agree and two are mixed. In three, groups with normal blood sugar on a glucose test still had high insulin or insulin resistance, in Finland, Qatar and Taiwan. In 6247 young American adults, 42.1% had insulin resistance, but that group included people with prediabetes, not only normal blood sugar.
Computed from 5 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
Every study and its exact words“And they found that anything over 87, there was a really linear increase in your risk of heart attacks, strokes and so forth over that, above 87.”
Mark Hyman, solo episode.
What 7 studies found
1 agree · 2 partly agree · 4 disagree
Four of seven studies disagree. The biggest, a pooled analysis of 102 studies, found no clear link between fasting blood sugar and heart attacks or strokes anywhere in the normal range. A pooled analysis adds up the results of many smaller studies. In 11,092 American adults, a level of 100 to 126 mg per deciliter raised the risk of diabetes, not of heart disease or stroke. One Korean study agrees: there, risk rose from a level near 90 mg/dL. Two studies are mixed.
Computed from 7 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
Every study and its exact wordsCloser look
The study that matches the episode's description followed young Israeli men. Higher fasting blood sugar, even inside the normal range, went with type 2 diabetes later on. It did not measure heart attacks or strokes.
7:24 “So typically on a glucose tolerance test, your blood sugar after two hours should never go over 140.” Said on tape, not checked yet.
The Crucial Importance of Testing Insulin and A1C
“So you start initially by having your insulin raise after you have a meal. But your fasting insulin and fasting glucose are normal.”
Mark Hyman, solo episode.
What 5 studies found
3 agree · 2 partly agree
Three studies agree and two are mixed. In 515 Israeli adults with normal blood sugar, fasting insulin was the strongest sign of who got type 2 diabetes over 24 years. In British civil servants, insulin output rose up to 7 years before diagnosis. In the two mixed studies, from Britain and Denmark, people who later got diabetes already had higher blood sugar and higher insulin when first tested, as early as 13 years before diagnosis. So those studies cannot say which rose first.
Computed from 5 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
Every study and its exact words“Even though 18 is considered quite normal, it's not. It should be five or less.”
Mark Hyman, solo episode.
What 10 studies found
3 agree · 7 partly agree
Higher fasting insulin goes with more heart disease and diabetes, but no study here tests the line said on the episode. Three of ten studies agree that risk rises with insulin across the whole range, including a pooled analysis of 22 studies. Seven are mixed. In several, insulin stopped predicting diabetes or death once other risk factors were counted. The studies that set a line put it higher: the top fifth of people, or 8 for men and 10 for women in one Brazilian study.
Computed from 10 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
Every study and its exact words13:12 “It's as good as the research test they use to measure insulin resistance in the lab, which is something called the euglycemic clamp test,” Said on tape, not checked yet.
15:21 “And a part of the reason is the solution is nutrition, not a drug.” Said on tape, not checked yet.
Understanding Hemoglobin A1C and Cardiovascular Risk
“Anybody over 5.1, the risk of cardiovascular disease went up in a linear fashion.”
Mark Hyman, solo episode.
What 10 studies found
4 agree · 5 partly agree · 1 disagree
A1C is a blood test that shows your average blood sugar over the last few months. Four of ten studies agree that heart risk starts inside the normal range. One found it for men above 5%, and another between 4.6% and 6.0%. Five are mixed: they place the rise higher, at 5.5% or 6.0%, or find a J-shape, where risk is also higher at the lowest levels. One study of 26,563 women found A1C predicted diabetes but not heart disease. No study used the cut-off said on the episode.
Computed from 10 studies that test this point, each judged by two readers, in full. 5 more studies are waiting for a full read and do not count yet.
Every study and its exact wordsFactors Affecting Post-Meal Blood Sugar and Lifestyle Impacts
“Like, there's a lot of science around how if you just take a ten to twenty minute walk after eating, everything will smooth out and you won't have these spikes in sugar and you'll really improve your metabolism.”
Mark Hyman, solo episode.
What 10 studies found
4 agree · 6 partly agree
Four of ten studies agree. In 41 adults with type 2 diabetes, walking after meals cut the rise in blood sugar by 12% compared with walking at other times. A review found the same in healthy people and in people with diabetes. Six are mixed, mostly because they tested a different walk: short breaks every half hour, or walks of 30 minutes or more. In one study of women over 50, a 15-minute walk lowered the spike, but not by enough to be sure it was real.
Computed from 10 studies that test this point, each judged by two readers, in full. 6 more studies are waiting for a full read and do not count yet.
Every study and its exact wordsCloser look
Adults with type 2 diabetes walking after each meal
“Overall postprandial glycaemia, as measured by the iAUC, was 12% (95% CI 1%, 22%) lower during the post-meal walking period than when following conventional physical activity advice.”
Diabetologia, 2016 · controlled trial · PMID 27747394
Older adults breaking up sitting with short walks
“In conclusion, breaking prolonged sitting with regular bouts of light walking, but not standing, reduced postprandial plasma insulin, glucose, and systolic blood pressure levels in a bi-ethnic population of older adults, with beneficial effects on postprandial insulin largest in South Asians who had higher levels of insulin resistance compared with white Europeans.”
J Gerontol A Biol Sci Med Sci, 2020 · controlled trial · PMID 30403772
Adults on long, slow walks after a meal
“In conclusion, we demonstrate for the time, to our knowledge, that slow-pace walking improves postprandial glucose excursion in healthy controls and people with type 1 diabetes.”
Diabetes Care, 2012 · trial or observed group · PMID 22875231
Key Metabolic Numbers and Ideal Ranges
“Your fasting insulin should be ideally under five, but under 10, you know, five to 10, you start to start paying attention, but not terrible.”
Mark Hyman, solo episode.
What 10 studies found
3 agree · 7 partly agree
Higher fasting insulin goes with more heart disease and diabetes, but no study here tests the line said on the episode. Three of ten studies agree that risk rises with insulin across the whole range, including a pooled analysis of 22 studies. Seven are mixed. In several, insulin stopped predicting diabetes or death once other risk factors were counted. The studies that set a line put it higher: the top fifth of people, or 8 for men and 10 for women in one Brazilian study.
Computed from 10 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
Every study and its exact words“Probably a good A1C is five. 5.1, 5.2 maybe, but I wouldn't go much higher than that”
Mark Hyman, solo episode.
What 10 studies found
4 agree · 5 partly agree · 1 disagree
A1C is a blood test that shows your average blood sugar over the last few months. Four of ten studies agree that heart risk starts inside the normal range. One found it for men above 5%, and another between 4.6% and 6.0%. Five are mixed: they place the rise higher, at 5.5% or 6.0%, or find a J-shape, where risk is also higher at the lowest levels. One study of 26,563 women found A1C predicted diabetes but not heart disease. No study used the cut-off said on the episode.
Computed from 10 studies that test this point, each judged by two readers, in full. 5 more studies are waiting for a full read and do not count yet.
Every study and its exact words26:33 “And if you're a man, you should have a ratio of less than point eight. If you're a woman, it should be less than point nine.” Said on tape, not checked yet.
29:54 “A lot of these people even have a higher risk of cardiovascular disease in their normal weight.” Said on tape, not checked yet.
30:52 “And there's a large Israeli study that looked at the microbiome and how much the microbiome influences individual variability when it comes to what your glucose will be.” Said on tape, not checked yet.
Actionable Steps to Reverse Insulin Resistance
“Second is, you know, take a walk after eating.”
Mark Hyman, solo episode.
What 10 studies found
4 agree · 6 partly agree
Four of ten studies agree. In 41 adults with type 2 diabetes, walking after meals cut the rise in blood sugar by 12% compared with walking at other times. A review found the same in healthy people and in people with diabetes. Six are mixed, mostly because they tested a different walk: short breaks every half hour, or walks of 30 minutes or more. In one study of women over 50, a 15-minute walk lowered the spike, but not by enough to be sure it was real.
Computed from 10 studies that test this point, each judged by two readers, in full. 6 more studies are waiting for a full read and do not count yet.
Every study and its exact words35:40 “If your APO B is high, you are likely insulin resistant because it measures all the dangerous lipid particles which are produced by eating sugar and starch that damage your lipids.” Said on tape, not checked yet.
Rapid Fire Metabolic Health Questions
“I mean, I've taken people who are type two diabetics, who are on insulin for ten years, who are so sick and massively overweight, and within three days they're off the insulin, in three months they're completely normal blood sugar.”
Mark Hyman, solo episode.
What 9 studies found
1 agree · 8 partly agree
Only one of nine studies agrees, and it followed 3 men: they stopped insulin after 5 to 18 days of fasting. Eight are mixed. In larger trials, people came off insulin over weeks or months, not days: 39.4% at 12 months in one trial, and 31 of 78 in another. Others cut their dose rather than stopping.
Computed from 9 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
Every study and its exact words“Walk for ten to twenty minutes after a meal.”
Mark Hyman, solo episode.
What 10 studies found
4 agree · 6 partly agree
Four of ten studies agree. In 41 adults with type 2 diabetes, walking after meals cut the rise in blood sugar by 12% compared with walking at other times. A review found the same in healthy people and in people with diabetes. Six are mixed, mostly because they tested a different walk: short breaks every half hour, or walks of 30 minutes or more. In one study of women over 50, a 15-minute walk lowered the spike, but not by enough to be sure it was real.
Computed from 10 studies that test this point, each judged by two readers, in full. 6 more studies are waiting for a full read and do not count yet.
Every study and its exact words43:33 “I'm so excited to share that my new book is officially available for preorder today.” Said on tape, not checked yet.
We go through the episode chapter by chapter and pull out each claim. For every claim we can test, two readers read each study in full and mark whether it agrees, partly agrees or disagrees. A fixed rule turns those marks into the badge, the same rule Precis uses on every page. Nobody writes or edits a badge. Chapters we haven't checked are shown in grey, so you can see everything the episode said.
Every quote is 20 seconds or less and opens the episode at that second. This is not medical advice. Talk to your doctor before you change anything.
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