Fasting brings gut hormones, above all insulin, to zero ('your fasting insulin equals zero').
Original statement
فالصيام يُصفّر الهرمونات المعوية، وعلى رأسها الأنسولين، فيمنح الكبد والأمعاء فرصة الإصلاح وإخراج السموم.
verbatim according to source. Translation by the project; the Arabic wording is authoritative.
Translation
Fasting brings gut hormones, above all insulin, to zero ('your fasting insulin equals zero').
Origin
- Source status
- Archive editors
- Attribution
- Archive editors summarising Elawady's view (homepage summary; not the quote box)
- Origin
- https://eltayebat.com/
- Attribution uncertainty
- Homepage summary written by the archive operators describing Elawady's views; partly cites his 'statement of the theory' video (aEbRfVSJIOw), otherwise no video reference.
- Claimed mechanism
Insulin is only secreted in response to food in the gut.
- Claimed health effect
Insulin falls to zero during fasting
- Population concerned
Everyone
- Geographic restriction by Elawady
none found
Diverging source versions
- Source status
- Video transcript (own words)
- Attribution
- Elawady (machine transcript)
- Video
- Dr Diaa Al Awady د ضياء العوضي is live!فلسفة الصيام مع السحور المحترم (Open source)
- Published
- 23 February 2026
- Timestamp
- not available (transcript has no timings)
- Attribution uncertainty
- Archive transcript (YouTube CC or AI-generated); no timestamps; 'published' is the date listed by the archive and may be the upload date. Live-stream transcripts can contain viewer comments read aloud; the quoted passage was checked in context to be spoken by Elawady.
- Source status
- Video transcript (own words)
- Attribution
- Elawady (machine transcript)
- Video
- ارتفاع السكر والأسيتون ؟خطر والا ده الطبيعي ؟#ضياء_العوضي (Open source)
- Published
- 23 December 2025
- Timestamp
- not available (transcript has no timings)
- Attribution uncertainty
- Archive transcript (YouTube CC or AI-generated); no timestamps; 'published' is the date listed by the archive and may be the upload date. Live-stream transcripts can contain viewer comments read aloud; the quoted passage was checked in context to be spoken by Elawady.
Scientific assessment
Mostly false – Essential parts of the statement are not supported by the evidence or are strongly exaggerated.
Certainty of evidence: high – Further research is very unlikely to change the assessment.
1. What was claimed?
Fasting reduces insulin (and other gut hormones) to zero.
2. What is demonstrably correct?
Insulin secretion falls during fasting, which permits lipolysis and ketone body production; ketones (beta-hydroxybutyrate) become a major brain fuel in prolonged starvation (I-FAST-01). Fasting regimens can lower fasting insulin (I-FAST-05).
3. What is wrong or exaggerated?
Insulin does not fall to zero in healthy people; a low basal level persists and restrains ketone production and hepatic glucose output. When insulin truly approaches zero (type 1 diabetes), ketoacidosis develops (I-INS-08). A fasting glucose of 700 mg/dL, which Elawady mentions as compatible with 'zero insulin', is a medical emergency indicating severe insulin deficiency, not a healthy fasting state. Insulin is also not only a gut hormone; it is a pancreatic hormone released into the portal vein, with secretion modulated by gut hormones (incretins).
4. What remains unclear?
Exact basal insulin values in individual lean people during very long fasts were not available in open abstracts; it is uncertain whether Elawady meant 'zero' literally or as 'very low'.
5. Which studies support it?
I-FAST-01 (insulin falls, ketones rise); I-FAST-103 (insulin and C-peptide decrease during a 72-h fast); partly I-FAST-05. No study reports insulin falling to zero.
6. Which studies contradict it?
I-FAST-101 (insulin plateau during 6-week fasts), I-FAST-102 (insulin secretion persists after 36 h), I-INS-08, I-INS-10.
7. What applies to Germany and Europe?
Not region-specific.
8. What is known about Egypt?
Not region-specific; Ramadan fasting practice is common.
9. What practical conclusion is appropriate?
Fasting lowers insulin, which is part of its metabolic effect, but a body without any insulin is in danger. People with diabetes on insulin must not stop basal insulin during fasting without medical advice.
Assessment details
- Rationale for certainty of evidence
Direct hormone measurements in fasting humans consistently show that insulin falls and then persists at a low plateau: during 6-week fasts insulin 'declined to a plateau by the 3rd day' (I-FAST-101); in a 72-h fast insulin and C-peptide decreased and reference intervals for the fasting period were reported (I-FAST-103); after 36 h only first-phase secretion was slightly reduced (I-FAST-102). Complete absence of insulin causes ketoacidosis (I-INS-08). The kernel (insulin falls) is correct, hence mostly false rather than false.
- Source quality
Homepage editorial paraphrase plus own words in machine transcripts.
- Regional transferability
Universal.
- Regional scope of the claim
- general (biological/medical)
- Last reviewed
- 26 October 2026 provisional
Scientific evidence in detail
Scientifically refuted – High-quality evidence shows the opposite, or the claim contradicts well-established physiology.
Research question: In healthy humans, does fasting reduce circulating insulin to zero?
Research question in detail (PECO)
- Population
- Healthy adults; people with diabetes for the safety implication
- Intervention or exposure
- Fasting 12 h to several weeks
- Comparison
- Fed / overnight-fasted state
- Geographic scope
- universal biology
- Outcomes
- Plasma insulin, C-peptide
- Insulin secretion
- Ketone production
Study results as reported by the authors. Our assessment follows below.
What speaks for the claim?
Normal hormone values during a three-day fast
Højlund K et al.. Am J Physiol Endocrinol Metab 2001 · PMID 11120658 · DOI 10.1152/ajpendo.2001.280.1.E50 Otherabstract checkednewly addedDuring a 72-h fast in 33 healthy adults insulin, C-peptide and proinsulin decreased.
- Actual result
- Decreases P<0.001; reference intervals reported (values not in abstract).
- Methodological quality
- moderate (physiological reference study)
- Relevance
- direct for the correct kernel (insulin falls)
- Limitations
- Values not extracted; abstract only.
How the body fuels itself during starvation
Cahill GF. Annu Rev Nutr 2006 · PMID 16848698 · DOI 10.1146/annurev.nutr.26.061505.111258 Narrative reviewabstract checkedInsulin falls in starvation and ketones become a major fuel.
- Actual result
- Narrative review, no numbers.
- Methodological quality
- low (narrative review)
- Relevance
- direct for the kernel
- Limitations
- Narrative.
What speaks against the claim?
Hormones during weeks of fasting
Marliss EB et al.. J Clin Invest 1970 · PMID 5480852 · DOI 10.1172/JCI106445 Otherabstract checkednewly addedDuring 6-week fasts insulin declined to a plateau by day 3 and stayed there.
- Actual result
- 'Insulin concentration declined to a plateau by the 3rd day.'
- Methodological quality
- moderate (classic physiological study)
- Relevance
- direct: insulin persists at a low level
- Limitations
- Old, small, abstract only.
Insulin after a 36-hour fast
Jørgensen SW et al.. Am J Physiol Endocrinol Metab 2021 · PMID 33284087 · DOI 10.1152/ajpendo.00433.2020 Otherabstract checkednewly addedAfter 36 h of fasting, insulin secretion persisted with only a minor fall in first-phase secretion.
- Actual result
- Minor reduction in first-phase secretion; higher insulin during refeeding.
- Methodological quality
- moderate (gold-standard methods, n=13)
- Relevance
- direct
- Limitations
- Small; men only.
Review on diabetic ketoacidosis
Dhatariya KK et al.. Nat Rev Dis Primers 2020 · PMID 32409703 · DOI 10.1038/s41572-020-0165-1 Narrative reviewfull text, structured risk-of-bias assessmentWhen insulin is truly absent (type 1 diabetes), diabetic ketoacidosis develops.
- Actual result
- D-K-A triad; DKA leading cause of death in young people with T1D.
- Methodological quality
- moderate (Nature Reviews primer)
- Relevance
- direct for the danger of zero insulin
- Limitations
- Narrative review.
What does the overall evidence say?
Editorial assessment based on the studies above – not itself a study result.
Which position is better supported?
Fasting lowers insulin substantially, which permits fat breakdown and ketone production (correct). Insulin does not fall to zero: a low basal level persists for weeks of fasting and restrains ketogenesis. A body with zero insulin develops ketoacidosis.
Why some studies weigh more
Direct hormone measurements in fasting humans (I-FAST-101, -102, -103) answer the question directly; the DKA literature explains why zero insulin is incompatible with health.
Is a causal relationship established? Not applicable Descriptive physiological question.
Remaining uncertainty
Exact basal insulin concentrations in individual lean people during very long fasts; whether Elawady meant 'zero' literally.
Justified conclusion
Insulin falls during fasting but does not reach zero; the 'zero' statement is physiologically false and dangerous when applied to people on insulin.
Why do studies seem to disagree?
None: all studies agree insulin falls; they differ only in duration and measurement method.
Does this depend on the country?
- General biological effects
- Universal endocrine physiology.
- Eating habits
- Ramadan fasting (daily, with night meals) is common in Egypt; it lowers insulin during the day without abolishing it.
- Origin of the food
- Not applicable.
- Contaminants
- Not applicable.
- National production conditions
- Not applicable.
- Legal rules
- Not applicable.
- Actual monitoring data
- No monitoring data relevant.
A regional difference that changes the conclusion is not supported by robust data.
Statistical re-check
- Numbers available? – Abstract reports qualitative time course only; no recalculation possible. not recalculable from the published data
- Numbers available? – Only P values in abstract; full text not openly accessible. not recalculable from the published data
Certainty of the overall evidence (GRADE, simplified)
- Main outcome
- Plasma insulin during fasting in healthy adults (zero vs low-persisting)
- Starting level
- low (observational studies)
- Reasons for upgrading
- consistent direct physiological measurements across studies and decades (no study reports zero)
- Result
- high
Simplified assessment by a single reviewer, following the GRADE approach; not a formal GRADE panel. GRADE rates the body of evidence for one outcome, not individual studies.
Clinical guidelines and official statements checked
- ADA: Standards of Care in Diabetes-2026, Section 6 (Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises) (2026) · Original publication
Previously verified by the diabetes team (I-INS-10 full text): people on intensive insulin therapy should not stop or hold basal insulin even if not eating; individuals at risk for DKA should measure ketones; consider holding SGLT2 inhibitors when oral intake cannot be maintained. Not re-fetched in this phase (diabetesjournals.org returned 403).
Search strategy
Documented literature searches for this review (search strings in the original database syntax).
| Database | Date | Search | Looking for | Hits | Included |
|---|---|---|---|---|---|
| Europe PMC | 26 October 2026 | ("72-hour fast" OR "72-h fast" OR "prolonged fast") AND (insulin) AND (healthy OR normal) AND (concentration OR "plasma insulin") AND (beta-hydroxybutyrate OR ketone) | both directions | 191 | |
| Europe PMC | 26 October 2026 | TITLE:(fasting) AND TITLE:(insulin) AND ("healthy subjects" OR "healthy volunteers") AND ("C-peptide") AND (days OR "84-hour" OR "48-hour" OR "60-hour") | both directions | 5 | |
| Europe PMC | 26 October 2026 | ("10-day fast" OR "water-only fast" OR "prolonged fasting" OR "long-term fasting") AND ABSTRACT:("insulin decreased" OR "insulin levels decreased" OR "insulin fell" OR "insulin concentrations") AND (healthy OR volunteers) AND (days) | both directions | 16 | |
| PubMed | 26 October 2026 | (fasting[ti] OR starvation[ti]) AND insulin[ti] AND (healthy OR normal) AND (suppression OR decrease) | supporting evidence | 221 | |
| PubMed | 26 October 2026 | "prolonged fasting"[tiab] AND ("insulin secretion"[tiab] OR "plasma insulin"[tiab]) AND humans[MeSH] | supporting evidence | 36 | |
| PubMed | 26 October 2026 | (fasting[ti] OR starvation[ti]) AND insulin[ti] AND ("C-peptide" OR "basal insulin" OR "insulin secretion") AND healthy | contradicting evidence | 48 | |
| PubMed | 26 October 2026 | ("insulin deficiency"[tiab] OR "type 1 diabetes"[tiab]) AND ketoacidosis[ti] AND (pathophysiology OR review[pt]) | contradicting evidence | 258 |
Open questions
Context of the 'fasting glucose 700 mg/dL' quote: if it refers to a real patient, it describes an emergency.
How deeply was this checked?
7 linked studies: 3 checked in full text (2 of them with a structured risk-of-bias assessment), 4 on the basis of the abstract, 0 bibliographically only. No formal assessment with two independent reviewers and no independent human expert review has taken place yet.
Last scientific review: 26 October 2026
History of the verdict
- 25 October 2026 · Phase 1 · Initial assessment: Mostly false (moderate)
- 26 October 2026 · Phase 4 (systematic evidence review) · Verdict changed: Mostly false (moderate) → Mostly false (high)
Previous certainty was moderate because 'no direct study measuring zero was reviewed'. Three direct physiological studies now registered (6-week fasts, 72-h reference intervals, 36-h secretion study) consistently show insulin persists at a low level. Verdict unchanged (the kernel 'insulin falls' is correct); certainty raised.
New sources: I-FAST-101 I-FAST-102 I-FAST-103
In plain language
When we do not eat, insulin goes down and the body starts burning stored fat. That part is correct. But insulin never reaches zero in a healthy person, because a small amount is always needed to keep acids in the blood under control. When insulin really is missing, as in type 1 diabetes, life-threatening ketoacidosis follows.
Studies on this claim
Studies supporting the claim (1)
-
How the body fuels itself during starvation
Cahill GF. Annu Rev Nutr 2006 · PMID 16848698 · DOI 10.1146/annurev.nutr.26.061505.111258Narrative reviewindependent cross-checkabstract checkedDuring long fasting the brain uses ketones from fat, which allows survival.
Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Fuel metabolism in prolonged starvation
- How was the study done?
Narrative/biographical review
- How many people, animals or samples were studied?
not applicable; Humans in starvation (historical studies)
- What was actually found?
Ketones fuel the brain in starvation.
- How large was the observed effect?
not reported
- What do the results mean in everyday life?
Fasting ketosis is normal physiology in healthy people.
- What are the study's limitations?
Narrative; No quantitative data in abstract
- What does it say about Elawady's specific claim?
Supports physiological kernels of C-FAST-01, C-FAST-03, C-FAST-04 (fasting ketosis is normal).
- Do the results apply to Germany and Europe?
Physiology universal.
- What can explicitly not be concluded from this study?
That high glucose plus ketones is harmless in diabetes.
No study in this group is marked as key.
Studies contradicting or limiting the claim (4)
-
Review on diabetic ketoacidosis
Dhatariya KK et al.. Nat Rev Dis Primers 2020 · PMID 32409703 · DOI 10.1038/s41572-020-0165-1Narrative reviewindependent cross-checkfull text, structured risk-of-bias assessmentDKA is an emergency that can kill; it is treated with fluids, insulin and salts, and insulin must not be stopped in type 1 diabetes even when not eating.
Does the study support the specific claim? No · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Epidemiology, pathogenesis, diagnosis and management of DKA
- How was the study done?
Narrative expert review (Nature Reviews Disease Primers)
- How many people, animals or samples were studied?
not applicable; Adults and children with diabetes
- What was actually found?
DKA is diagnosed by high glucose, ketones and acid; it kills <1% when treated in rich countries but up to 26-41% where treatment is lacking; treatment is fluids, insulin and potassium, and insulin must never be stopped in type 1 diabetes even when not eating.
- How large was the observed effect?
not applicable
- What do the results mean in everyday life?
DKA is an emergency.
- What are the study's limitations?
Narrative expert review without systematic methods; one author has research support from insulin makers.
- What does it say about Elawady's specific claim?
- Do the results apply to Germany and Europe?
International.
- What can explicitly not be concluded from this study?
Quantitative estimates.
-
ADA guideline 2026: blood sugar goals and emergencies
American Diabetes Association Professional Practice Committee for Diabetes* . Diabetes Care 2026 · PMID 41358894 · DOI 10.2337/dc26-S006Guideline / position statementindependent cross-checkfull text checked★ key studyMost adults should aim for HbA1c below 7%, avoid low sugar, and measure ketones when at risk.
Does the study support the specific claim? Partly · Methodological quality: high · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Glycaemic goals, hypoglycaemia and hyperglycaemic crises
- How was the study done?
Clinical practice guideline (ADA Standards of Care 2026, Section 6)
- How many people, animals or samples were studied?
not applicable; People with diabetes
- What was actually found?
Individual targets; do not stop basal insulin when not eating.
- How large was the observed effect?
not applicable
- What do the results mean in everyday life?
Moderate targets and safety rules.
- What are the study's limitations?
US-centred; Partially read
- What does it say about Elawady's specific claim?
Supports C-INS-04, C-INS-11; contradicts C-FAST-01, C-FAST-03, C-DIAB-02.
- Do the results apply to Germany and Europe?
Consistent with EASD guidance.
- What can explicitly not be concluded from this study?
Not applicable.
-
Hormones during weeks of fasting
Marliss EB et al.. J Clin Invest 1970 · PMID 5480852 · DOI 10.1172/JCI106445Otherindependent cross-checkabstract checked★ key studyDuring fasts of up to six weeks, insulin fell to a low plateau by the third day and stayed there; glucagon rose.
Insulin declines to a plateau by day 3 of fasting and persists; it does not go to zero.
Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Describe glucagon and insulin in prolonged human fasting.
- How was the study done?
Repeated blood measurements during supervised fasts; glucagon infusions.
- How many people, animals or samples were studied?
Volunteers on 6-week fasts (number not in abstract).
- What was actually found?
Insulin fell to a plateau by day 3; glucagon peaked on day 3.
- How large was the observed effect?
Not reported in abstract.
- What do the results mean in everyday life?
Fasting lowers insulin, but a low basal level remains.
- What are the study's limitations?
Old, small, uncontrolled; abstract only.
- What does it say about Elawady's specific claim?
Correct that insulin falls; wrong that it becomes zero.
- Do the results apply to Germany and Europe?
Applies; same physiology.
- What can explicitly not be concluded from this study?
Exact insulin concentrations; effects in lean people.
-
Insulin after a 36-hour fast
Jørgensen SW et al.. Am J Physiol Endocrinol Metab 2021 · PMID 33284087 · DOI 10.1152/ajpendo.00433.2020Otherindependent cross-checkabstract checked★ key studyIn 13 healthy men, a 36-hour fast only slightly reduced early insulin release; the body became more insulin resistant for a while.
Insulin secretion persists after 36 h; only a minor fall in first-phase secretion.
Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Understand how insulin release and action change with a longer fast.
- How was the study done?
Compared 36-h and 12-h fasts with glucose tolerance testing and tracers.
- How many people, animals or samples were studied?
13 healthy young men in Denmark.
- What was actually found?
Insulin secretion persisted with a minor reduction; whole-body insulin resistance increased.
- How large was the observed effect?
Not available (abstract only).
- What do the results mean in everyday life?
Healthy bodies keep making some insulin even after a day and a half without food.
- What are the study's limitations?
Tiny sample, men only, short fast.
- What does it say about Elawady's specific claim?
Insulin does not go to zero; physiological insulin resistance during fasting is real but different from diabetes.
- Do the results apply to Germany and Europe?
Applies; same physiology.
- What can explicitly not be concluded from this study?
Effects of fasts longer than 36 h; women; people with diabetes.
No study in this group is marked as key.
Studies with mixed or unclear results (2)
-
What intermittent fasting does to metabolism
Patterson RE et al.. Annu Rev Nutr 2017 · PMID 28715993 · DOI 10.1146/annurev-nutr-071816-064634Narrative reviewindependent cross-checkfull text, structured risk-of-bias assessmentFasting regimens seem to help weight loss and may improve metabolism; much is still hypothesis.
Does the study support the specific claim? Partly · Methodological quality: low · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Metabolic effects of intermittent fasting
- How was the study done?
Narrative review
- How many people, animals or samples were studied?
not applicable; Humans and animal models
- What was actually found?
Most small fasting trials showed some weight loss; fasting was not better than eating less every day; benefits for liver and metabolism come mainly from mouse studies.
- How large was the observed effect?
not reported
- What do the results mean in everyday life?
A possible tool, not a cure.
- What are the study's limitations?
Not a systematic review; small, short human studies; much evidence from male mice; no long-term disease outcomes.
- What does it say about Elawady's specific claim?
Partial support for C-FAST-02, C-FAST-05; kernel of C-FAST-01.
- Do the results apply to Germany and Europe?
General.
- What can explicitly not be concluded from this study?
Superiority or detox effects.
-
Normal hormone values during a three-day fast
Højlund K et al.. Am J Physiol Endocrinol Metab 2001 · PMID 11120658 · DOI 10.1152/ajpendo.2001.280.1.E50Otherindependent cross-checkabstract checkedIn 33 healthy adults fasting 72 hours, glucose and insulin went down while stress hormones went up.
Insulin, C-peptide and proinsulin decrease during a 72-h fast, with reference intervals given; decline, not disappearance.
Does the study support the specific claim? Partly · Methodological quality: moderate · Certainty of evidence: see overall assessment of the claim
Original publication · Scientific details
Study explained simply
- What did the researchers want to find out?
Define normal values during the 72-hour fast test.
- How was the study done?
Repeated blood sampling during a 72-h fast.
- How many people, animals or samples were studied?
33 healthy Danish adults.
- What was actually found?
Glucose, insulin and C-peptide decreased; glucagon, FFA, cortisol, catecholamines increased.
- How large was the observed effect?
P<0.001 for decreases (values not in abstract).
- What do the results mean in everyday life?
When healthy people fast, insulin and blood sugar go down, not up.
- What are the study's limitations?
Values not available from abstract.
- What does it say about Elawady's specific claim?
Insulin falls but is measured throughout; blood sugar falls in healthy fasting.
- Do the results apply to Germany and Europe?
Applies; same physiology.
- What can explicitly not be concluded from this study?
Whether insulin ever reaches undetectable levels in individuals.
No study in this group is marked as key.
Regional context
Germany / EU
Not region-specific.
Egypt
Not region-specific; Ramadan fasting practice is common.
What applies in my country?
General scientific assessment
Mostly false Fasting lowers insulin, but measurements show it settles at a low level and does not fall to zero; zero insulin means ketoacidosis.
This statement concerns biological or medical relationships. The scientific assessment above applies regardless of the country; country-specific food data do not change it.
References
- Fuel metabolism in starvation.. Cahill GF. Annu Rev Nutr 2006 · PMID 16848698 · DOI 10.1146/annurev.nutr.26.061505.111258
- Diabetic ketoacidosis.. Dhatariya KK et al.. Nat Rev Dis Primers 2020 · PMID 32409703 · DOI 10.1038/s41572-020-0165-1
- 6. Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes-2026.. American Diabetes Association Professional Practice Committee for Diabetes* . Diabetes Care 2026 · PMID 41358894 · DOI 10.2337/dc26-S006
- Glucagon levels and metabolic effects in fasting man.. Marliss EB et al.. J Clin Invest 1970 · PMID 5480852 · DOI 10.1172/JCI106445
- Impact of prolonged fasting on insulin secretion, insulin action, and hepatic versus whole body insulin secretion disposition indices in healthy young males.. Jørgensen SW et al.. Am J Physiol Endocrinol Metab 2021 · PMID 33284087 · DOI 10.1152/ajpendo.00433.2020
- Metabolic Effects of Intermittent Fasting.. Patterson RE et al.. Annu Rev Nutr 2017 · PMID 28715993 · DOI 10.1146/annurev-nutr-071816-064634
- Reference intervals for glucose, beta-cell polypeptides, and counterregulatory factors during prolonged fasting.. Højlund K et al.. Am J Physiol Endocrinol Metab 2001 · PMID 11120658 · DOI 10.1152/ajpendo.2001.280.1.E50