Whole Food, High Carb, Plant-Based Diets vs. a Ketogenic Diets. They Both Can Work!What Does the Fat in Your Muscle and Liver Cells Have to Do with Insulin Sensitivity or Resistance?… A Lot!…
Hana Kahleova, MD, PhD
Endocrinologist (MD) / Human Physiology (PhD)
Physicians Committee for Responsible Medicine
5100 Wisconsin Ave NW, Ste 400Washington, DC 20016
hkahleova@pcrm.org; hana.kahleova@gmail.com
Vegan diet, processed foods, and type 1 diabetes: A secondary analysis of a randomized clinical trial.
Nutr Metab Cardiovasc Dis. 2025 Nov;35(11):104197.
Perspective: Plant-Based Eating Pattern for Type 2 Diabetes Prevention and Treatment:
Efficacy, Mechanisms, and Practical Considerations.
Adv Nutr. 2021 Dec 1;12(6):2045-2055.
Kirk Hamilton: How long have you been studying whole food plant-based diets and diabetes?
Hana Kahleova: I’ve been working in clinical nutrition and metabolic research for almost two decades, focusing specifically on randomized clinical trials of plant-based diets in diabetes. My work has examined mechanisms—such as insulin sensitivity, ectopic fat, and postprandial metabolism—as well as clinical outcomes including weight, glycemic control, and medication use.
KH: Where did the idea that carbohydrates cause diabetes come from?
HK: That idea largely comes from the observation that carbohydrates acutely raise blood glucose. But acute glucose response is not the same as the underlying cause of diabetes. The root problem in type 2 diabetes is insulin resistance, not carbohydrate intake per se.
KH: Does fruit cause diabetes?
HK: Whole carbohydrates—especially from intact plant foods like fruit—are consistently associated with lower diabetes risk in epidemiologic studies. Fruit does not cause diabetes; in fact, it’s generally protective when consumed as part of a whole-food dietary pattern.
KH: Can you define insulin sensitivity vs. resistance, and why a high-carb, low-fat diet can help?
HK: Insulin sensitivity means cells respond effectively to insulin, allowing glucose to enter the cell. Insulin resistance means cells do not respond well, so glucose remains in the bloodstream.
A low-fat, whole-food plant-based diet can improve insulin sensitivity by reducing intracellular fat accumulation, particularly in muscle and liver, which interferes with insulin signaling. When that fat is reduced, glucose uptake improves—even with higher carbohydrate intake.
KH: How does dietary fat and muscle fat affect insulin resistance?
HK: Excess fat—especially saturated fat—can accumulate inside muscle and liver cells as intramyocellular and hepatocellular lipid. These lipid intermediates disrupt insulin signaling pathways.
This is a key mechanism: it’s not just body fat, but fat inside cells that drives insulin resistance. Reducing dietary fat, particularly saturated fat, helps mobilize these lipid stores and restore insulin sensitivity.
KH: Why do you encourage a low-fat diet for diabetes?
HK: Because it directly targets one of the root mechanisms of insulin resistance. Lowering dietary fat reduces lipid accumulation in insulin-sensitive tissues and improves metabolic function.
Importantly, this approach allows patients to eat satiating volumes of food without calorie restriction, which supports adherence and long-term sustainability.
KH: How do you explain that both ketogenic and plant-based diets can “reverse” diabetes? Which is better?
HK: Both approaches can improve glycemic control, but through different mechanisms:
– Ketogenic diets reduce glucose exposure by restricting carbohydrates.
– Plant-based diets improve the body’s ability to handle glucose by improving insulin sensitivity.
The key difference is mechanism and long-term physiology. Plant-based diets address the underlying metabolic dysfunction and are associated with broader benefits—cardiovascular risk reduction, weight loss, and improved insulin sensitivity—without requiring severe restriction.
So the question is not just “Does it work?” but “How does it work—and what are the long-term implications?”
KH: Have you studied reversal of diabetes with a plant-based diet?
HK: Yes. In randomized clinical trials, we’ve shown that a low-fat vegan diet leads to significant improvements in HbA1c, body weight, insulin sensitivity, and lipid profiles in individuals with type 2 diabetes. Some people experience a complete diabetes reversal, and everybody experiences at least significant improvements in their diabetes.
In type 1 diabetes, we’ve demonstrated that a low-fat plant-based diet can significantly reduce insulin requirements and improve glycemic control, largely through improved insulin sensitivity.
KH: Do patients with type 1 diabetes need to reduce insulin when starting?
HK: Yes—this is critical. Insulin sensitivity can improve rapidly, sometimes within days. Patients must be closely monitored and often need prompt insulin dose adjustments to avoid hypoglycemia. This should always be done under medical supervision.
KH: How do you get a patient started on a WFPBD?
HK: I keep it practical and structured:
– Base meals on vegetables, fruits, legumes, and whole grains
– Minimize added fats and highly processed foods
– Provide simple meal templates and support
Equally important is follow-up and guidance, especially for patients on glucose-lowering medications.
KH: Any final thoughts?
HK: We are entering a new era in diabetes care, with powerful pharmacologic tools like GLP-1 receptor agonists. But alongside that, we should not overlook interventions that target the underlying biology of the disease.
Nutrition—when applied systematically and supported properly—is not just an adjunct. It can be a central therapeutic strategy that improves metabolic function across multiple pathways simultaneously.
The goal is not just to lower blood sugar—it’s to restore metabolic health. And that requires looking beyond a single pathway.
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Kirk’s Quick Thoughts on Improving Blood Sugar and Carbohydrate Consumption
1) One of my goals is to get a patient’s Hemoglobin A1 and fasting insulin both ≤ 5 no matter what whole food dietary pattern you consume. Usually this means eliminating all processed carbohydrates and processed foods. Sometimes even whole grains need to be cut back.
2) Emphasize patients to eat “whole” “intact” carbohydrate rich foods. Simple rule. Hard to follow. We are surrounded by processed carbohydrates with added oils, usually unhealthy ones, added forms of sugar, sometimes food additives and a product devoid of fiber.
3) Walk after meals, even 10-15 minutes can help reduce blood sugar.
4) Build some lean body mass. Minimally do some muscle building with body weight exercises and/or circuit weight training. I tell patients keep it simple. 20 minutes 3 times per week. Do six full range of motion exercises on the machines for the arms, 6-10 repetitions and six for the legs. I tell people don’t stop between your exercises. Get off one machine and move to the other. Ideally alternating between arm exercises and leg exercises. With time increase the weight and intensity. But if just starting do light weight and just get the full range of motion for the first 2-3 weeks then start to increase the intensity.
5) Weight yourself daily without judgement. Almost any weight loss with whole food consumption with reduce your A1C and insulin levels.
6) Fasting insulin level can drop within a week. An A1C, the average blood sugar over a 3-4 month period (the life of the red blood cell which the sugar attaches to) I have seen drop in 2-3 weeks significantly. Sometimes I will repeat a test like an A1C which are usually on done every 3-4 months at the earliest in 2-4 weeks to show and help motivate a patient that with a whole food diet and weight loss you can change your blood sugar physiology within weeks in a test designed to be repeated after 3-4 months.
7) I believe in whole food plant-based nutrition for a variety of reasons, but I don’t think it can be said that whole food plant-based diets make people live longer versus small amounts of animal food consumed several times per week or even daily. Both diets whether some animal food daily or not should be in the context of the rest of the food being whole, varied and with lots of color and fiber. It’s noted that one of the highest per capita animal food consumption is in Hong Konger which are at the top or near the top of life expectancy….But you can’t take one component of a lifestyle and say that is the reason for longevity. Again, eat whole, intact foods, lots of variety and I don’t think it matters from a health perspective if one eats small amounts of animal food daily. I would go with you’re your body feels strictly coming from a health perspective.
Kirk Hamilton PA-C
Health Associates Medical Group
3301 Alta Arden, Suite 3
Sacramento, CA 95825
(916) 489-4400 (w)
krhammer@surewest.net
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