Is the Keto Diet Good or Bad for Type 2 Diabetes? A Straight-Talk Guide to Pros and Cons

By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group
Published: June 18, 2025Updated: June 18, 2025

Summary

A well-planned ketogenic diet can lower A1C by 0.5–1.5 % and reduce insulin needs for many adults with type 2 diabetes, but it also raises the risk of hypoglycemia, nutrient gaps, and LDL-C increases. Close monitoring, medication adjustment, and lab work every 3 months are mandatory to keep benefits ahead of the downsides.

Does keto reliably improve blood sugar control in type 2 diabetes?

Most clinical trials show better short-term glucose control on keto, but results vary by study length and adherence. Benefits hinge on staying under 30 g net carbs per day and monitoring medications.

  • A1C often drops within 12 weeksRandomized data show average A1C reductions of 0.9 % after 3 months on keto compared with 0.3 % on a moderate-carb diet. “Because carbs drive post-meal glucose spikes, strict limitation can deliver rapid wins,” explains the team at Eureka Health.
  • Fewer glucose-lowering drugs may be neededUp to 57 % of participants in a 2022 meta-analysis reduced or stopped at least one diabetes medication while on keto.
  • Fasting insulin falls in most studiesLower insulin demand can improve weight loss and may slow beta-cell burnout, says Sina Hartung, MMSC-BMI: “Less exogenous insulin often means fewer lows and less weight gain.”
  • Long-term evidence is still limitedOnly two trials extend beyond two years, so durability of benefits is uncertain.
  • Average weight loss is about 7 kg greater than with other dietsA meta-analysis of 14 randomized trials reported that people with type 2 diabetes lost roughly 7 kilograms more on ketogenic diets than on comparator eating plans, an effect that can further enhance insulin sensitivity. (DietDoctor)

References

Could keto backfire or become dangerous for my diabetes?

Rapid carb restriction changes insulin needs within days. Without dose adjustments, serious lows or rare ketoacidosis events can occur.

  • Hypoglycemia is the top immediate riskOne study reported glucose <54 mg/dL in 30 % of insulin users during the first week of keto.
  • LDL-C may climb by 10–30 mg/dLHigher saturated-fat intake can raise LDL in roughly one-third of adults; the team at Eureka Health notes that “a fasting lipid panel at baseline and 8 weeks later catches the upward trend early.”
  • Electrolyte imbalance triggers ‘keto flu’Sodium, potassium, and magnesium losses can cause cramps and palpitations; supplementing 1–2 g sodium and 300 mg magnesium daily often resolves symptoms, according to Sina Hartung, MMSC-BMI.
  • Euglycemic ketoacidosis is rare but realSGLT-2 inhibitors plus carb restriction have produced case reports of normal-glucose DKA—seek urgent care for rapid breathing, nausea, or abdominal pain.
  • Medication needs can drop within the first monthA 2021 review summarized by Healthline noted that many people were able to reduce or discontinue diabetes medications as early as 3 weeks after starting keto, highlighting the importance of actively titrating doses with a clinician. (Healthline)
  • Type 1 diabetes faces the highest ketoacidosis dangerCleveland Clinic cautions that diabetic ketoacidosis is “more common for people with Type 1 diabetes,” meaning those patients require especially close ketone and glucose monitoring when attempting very-low-carb eating patterns. (ClevelandClinic)

References

Which common keto side effects are usually harmless?

Not every symptom is a red flag. Many mild issues fade with tweaks to fluids, fiber, and meal timing.

  • Transient fatigue during week 1Glycogen depletion lowers energy for 3–5 days in most people but resolves as ketone adaptation occurs.
  • Metallic breath signals ketosisAcetone exhalation causes ‘keto breath’; sugar-free mints help and the odor fades after a month, says the team at Eureka Health.
  • Mild constipation is commonFiber often drops below 15 g/day on keto. Adding chia, avocado, and low-carb veggies usually restores regularity.
  • Benign increase in uric acidLevels may rise by 1 mg/dL but rarely cause gout in people without prior flares, notes Sina Hartung, MMSC-BMI.
  • Temporary headaches often appear in the first few daysHealthline lists headache, dizziness, and nausea as part of the short-lived “keto flu,” typically clearing within a week once hydration and electrolytes are adjusted. (Healthline)
  • Early-stage insomnia usually resolves as adaptation occursHarvard Health reports sleep problems are among the common, benign side effects that improve after the body shifts from glucose to ketone fuel. (HarvardHealth)

References

How can I start keto safely with type 2 diabetes?

Preparation reduces risks and boosts adherence. Map out carbs, check meds, and schedule follow-up.

  • Taper carbs over 7 days instead of overnightDropping from 200 g to 30 g net carbs gradually gives time to adjust insulin and sulfonylurea doses.
  • Use a plate method to hit macrosAim for 70 % fat, 20 % protein, 10 % carbs: half the plate non-starchy vegetables, one-quarter protein, the rest healthy fats.
  • Check glucose 4 times daily at first“Frequent finger-sticks or CGM alerts catch rapid changes before they become emergencies,” says the team at Eureka Health.
  • Include potassium-rich low-carb foodsSpinach, salmon, and pumpkin seeds replace electrolytes lost in early ketosis.
  • Schedule medical review after 2 weeksSina Hartung, MMSC-BMI advises a med check once fasting glucose drops below 100 mg/dL on two consecutive mornings.
  • Six-month keto can cut HbA1c by about 1.5 percentage pointsA 2008 study summarized by Diabetes.co.uk found adults with type 2 diabetes lowered average HbA1c by 17 mmol/mol (≈1.5%) after six months on a ketogenic plan, underscoring the need to coordinate lab work with your care team. (DCUK)
  • Ketone testing helps rule out dangerous ketoacidosisHealthline recommends keeping urine or blood ketone strips handy and testing whenever glucose runs high, so you can distinguish safe nutritional ketosis from diabetic ketoacidosis and seek care quickly if needed. (HL)

References

What labs and medication changes matter most on keto?

Lab trending and dose tweaks keep the diet therapeutic instead of hazardous.

  • Baseline and 3-month CMP plus fasting lipidsTrack ALT, creatinine, and LDL-C; ALT rise >35 U/L or LDL-C >190 mg/dL warrants a diet re-evaluation.
  • CGM or SMBG drives insulin reductionsMany people cut basal insulin by 20–50 % within the first month; all changes should be clinician-supervised.
  • Sulfonylureas may be stopped entirelyBecause they drive insulin release regardless of carbs, they carry a high hypo risk on keto, warns the team at Eureka Health.
  • Metformin usually staysIt complements keto by lowering hepatic glucose output and has no hypo risk, notes Sina Hartung, MMSC-BMI.
  • HbA1c can fall by about 1.5 % within a yearA 2008 study cited by Diabetes.co.uk found an average 17 mmol/mol (≈1.5 %) drop in HbA1c after a ketogenic diet, letting many participants scale back or stop diabetes medications. (Diabetes.co.uk)
  • Triglycerides drop while HDL climbs on ketoA meta-analysis of 14 randomized trials reported larger triglyceride reductions and HDL increases on ketogenic diets versus other eating plans, underscoring why follow-up lipid panels matter. (DietDoctor)

References

How can Eureka’s AI doctor support my keto transition?

The AI doctor inside the Eureka app reviews your food logs, glucose readings, and symptoms in real time, then suggests evidence-based adjustments.

  • Automated carb counting from meal photosUpload a plate photo and Eureka estimates net carbs within seconds so you spot hidden starches.
  • Medication adjustment promptsIf fasting glucose trends below 90 mg/dL for two mornings, the AI flags possible hypoglycemia risk and recommends contacting your clinician.
  • Personalized electrolyte reminders“Our algorithm nudges users to add magnesium-rich foods if they report cramps,” explains the team at Eureka Health.

Why do people with type 2 diabetes keep using Eureka during keto?

Eureka offers private, continuous guidance that many clinics can’t match between visits.

  • High satisfaction among diabetes usersIn-app surveys show a 4.7 / 5 average rating for glucose management support.
  • On-demand lab orderingRequest an A1C or lipid panel; a licensed physician reviews and, if appropriate, orders the test—no phone tag.
  • Safe prescription workflowsThe AI can suggest dose changes; a board-certified doctor confirms before anything is sent to your pharmacy.
  • Trusted information repositorySina Hartung, MMSC-BMI notes, “Patients like that Eureka stores their keto macros, labs, and meds in one secure place.”}] ,

Why do people with type 2 diabetes keep using Eureka during keto?

Eureka offers private, continuous guidance that many clinics can’t match between visits.

  • High satisfaction among diabetes usersIn-app surveys show a 4.7 / 5 average rating for glucose management support.
  • On-demand lab orderingRequest an A1C or lipid panel; a licensed physician reviews and, if appropriate, orders the test—no phone tag.
  • Safe prescription workflowsThe AI can suggest dose changes; a board-certified doctor confirms before anything is sent to your pharmacy.
  • Trusted information repositorySina Hartung, MMSC-BMI notes, “Patients like that Eureka stores their keto macros, labs, and meds in one secure place.”}]}],

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Frequently Asked Questions

Can I stay on keto forever if my A1C improves?

Long-term safety data are limited. Reevaluate labs and symptoms every 6–12 months with your clinician to decide how long to continue.

Should I stop metformin once I’m in ketosis?

Usually no. Metformin does not cause lows and supports liver health, but dosage can be reviewed if GI side effects worsen.

Is keto safe if I take an SGLT-2 inhibitor?

It can raise the chance of euglycemic ketoacidosis. Discuss risk-mitigation strategies and consider closer ketone monitoring.

How much protein is too much on keto for diabetes?

Keep protein at 1.0–1.5 g per kg ideal body weight. Exceeding this may hinder ketosis without added glucose benefit.

What should my blood ketone level be?

Nutritional ketosis is 0.5–3.0 mmol/L. Levels above 3.0 mmol/L with nausea or vomiting require medical evaluation.

Can keto reverse neuropathy?

Tighter glucose control may slow progression, but established nerve damage rarely reverses completely.

Will my insurance cover labs ordered through Eureka?

Coverage depends on your plan; the app provides itemized codes to submit for reimbursement.

Is vegetarian keto possible with diabetes?

Yes. Use eggs, tofu, tempeh, nuts, and olive oil to reach fat and protein targets while limiting carb-dense legumes.

How quickly should I reduce basal insulin when starting keto?

Some clinicians pre-emptively cut basal by 20 % on day 1, then fine-tune based on glucose readings. Always coordinate with your provider.

This content is for informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider for diagnosis, treatment, and personalized medical recommendations.

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