Carnivore and Blood Sugar / Insulin Resistance

If there is one area where the mechanism behind carnivore eating is straightforward, it is blood sugar. Dietary carbohydrate is the main driver of the rise in blood glucose after meals. Remove almost all of it and glucose spikes largely disappear. Whether that translates into better long-term health is a separate and more interesting question.

The basic physiology

When you eat carbohydrate, it is digested to glucose, blood glucose rises, and the pancreas releases insulin to move glucose into cells. In insulin resistance, cells respond poorly to insulin, so the body needs more of it to do the same job. Over years, this can progress to prediabetes and type 2 diabetes.

A carnivore diet supplies almost no carbohydrate. The body still needs some glucose, and it makes what it needs from protein and glycerol (gluconeogenesis). Blood glucose stays in a relatively narrow range, and insulin levels generally fall. Protein does stimulate some insulin release, but the overall insulin load is usually lower than on a mixed diet.

What the trials show (for low-carb diets)

There are no large randomized trials of a carnivore diet for diabetes. There is, however, a substantial body of trials of low- and very-low-carbohydrate diets, which is the closest evidence we have.

• Diabetes remission: a 2021 systematic review and meta-analysis in The BMJ pooled randomized trials in type 2 diabetes. Low-carbohydrate diets achieved higher rates of remission at six months than comparison diets, along with weight loss and lower triglycerides and medication use. By twelve months the advantages were smaller and less certain, and the authors noted concerns about long-term sustainability and some quality-of-life measures^[1].
• Supported ketogenic care: a non-randomized one-year study of people with type 2 diabetes following a ketogenic diet with remote medical supervision reported average HbA1c falling from about 7.6% to about 6.3%, weight loss of around 12%, and large reductions in diabetes medication use, including insulin^[2]. Because participants chose their group, this is weaker than an RCT, but it shows what can happen with close support.
• Lower glucose and insulin in a metabolic ward: in a tightly controlled NIH study, an animal-based ketogenic diet produced lower glucose and insulin levels than a plant-based low-fat diet^[3].

Carnivore-specific data

In the 2021 carnivore survey, respondents with diabetes reported lower HbA1c and most reported reducing or stopping diabetes medications^[4]. This is consistent with the trial data on low-carb diets, but remember it is self-reported and self-selected.

An important caveat: measurement quirks

Some people on very-low-carbohydrate diets notice their fasting glucose is a little higher than expected, even while their HbA1c and post-meal glucose are excellent. One explanation often proposed is "physiological insulin resistance" or "glucose sparing", where muscles preferentially burn fat and leave glucose for the brain. This is plausible mechanistically but not well characterised in carnivore eaters specifically.

A practical consequence: a standard oral glucose tolerance test (drinking 75 g of glucose) may look worse than expected if you have been eating near-zero carbohydrate beforehand. If you need one, tell your doctor about your diet; they may advise eating some carbohydrate for a few days beforehand, as is standard practice for that test.

What to measure

Medication safety: the part you must not skip

This is the most important section of this article. If you take medication for diabetes, a sudden switch to near-zero carbohydrate can be dangerous without adjustment.

• Insulin and sulfonylureas (such as gliclazide or glipizide) can cause hypoglycemia when carbohydrate intake drops. Doses often need to be reduced, sometimes on day one. A practical guide for doctors in the British Journal of General Practice describes how clinicians can adjust these drugs when patients adopt a low-carbohydrate diet^[6].
• SGLT2 inhibitors (empagliflozin, dapagliflozin, canagliflozin and others) carry an FDA warning about ketoacidosis, which can occur even when blood glucose is not very high^[7]. Combining these drugs with a ketogenic diet requires explicit medical discussion.
• Blood pressure medications may need reducing, as blood pressure often falls on low-carbohydrate diets.

Never stop or change diabetes medication on your own. Work with your doctor, monitor glucose closely in the first weeks, and have a plan for what to do if readings run low.

Type 1 diabetes

Some people with type 1 diabetes use very-low-carbohydrate diets to smooth out glucose swings, and some reported this in the carnivore survey^[4]. This requires particularly careful insulin management and medical supervision, because the risks of hypoglycemia and ketoacidosis are real.

The bottom line

• Very-low-carbohydrate eating reliably lowers post-meal glucose and usually lowers insulin.
• Randomized trials of low-carb diets show meaningful short-term improvements and remission in type 2 diabetes; long-term advantages are less certain.
• Carnivore-specific evidence is limited to self-reports, which are consistent with the trial data.
• Medication adjustment under medical supervision is essential for anyone on glucose-lowering drugs.