The Myth That Keto Causes Heart Disease

The ketogenic diet often faces criticism for supposedly increasing heart disease risk. This concern stems from outdated assumptions about dietary fat and cholesterol. In reality, multiple studies show carbohydrate restriction improves key cardiovascular markers more effectively than low-fat diets.

How the Myth Began

The idea that saturated fat causes heart disease dates to the 1950s. Early observational studies linked high-fat diets to cardiovascular issues, but these failed to distinguish between types of fat or account for sugar intake. The NHS still recommends limiting saturated fat to 30 g daily for men and 20 g for women, despite growing contradictory evidence.

A 2017 meta-analysis in Nutrients found ketogenic diets typically reduce triglycerides by 20-30% and raise HDL (good cholesterol) by 10-15%. LDL particle size often shifts toward larger, less atherogenic forms. These changes occurred even when participants ate foods like butter and red meat.

What the Research Shows

Kosinski and Jornayvaz (2017) analysed 48 human and animal studies on ketogenic diets and cardiovascular risk factors. Their review found consistent improvements in:

Triglyceride levels
HDL cholesterol
Blood pressure
Inflammation markers

Some individuals see temporary LDL increases during weight loss phases, but these typically stabilise within months. Those with genetic predispositions to high cholesterol (like familial hypercholesterolaemia) should monitor levels more closely.

What This Means in Practice

A well-formulated ketogenic diet emphasises whole foods: fatty fish, nuts, olive oil, and leafy greens. At Tesco, you’ll find fresh mackerel for £2.50 per 300 g portion – an excellent source of omega-3s. Seasonal British vegetables like kale and Brussels sprouts provide fibre without excess carbs.

Processed meats and fried foods aren’t inherent to keto, despite popular portrayals. The best fats for keto include avocado oil, ghee, and fatty fish. These provide anti-inflammatory benefits absent in industrial seed oils.

Addressing Common Concerns

Critics often cite the high saturated fat content of some keto foods. Yet controlled trials show no correlation between natural saturated fats and heart disease when carbohydrate intake remains low. The body processes fats differently in ketosis versus glycolytic states.

For those worried about cholesterol, prioritising monounsaturated fats (like those in olive oil and macadamias) may help. Regular blood tests provide personalised feedback – something the NHS offers free to those with existing conditions.

Frequently Asked Questions

Doesn’t keto raise LDL cholesterol?

Short-term increases sometimes occur during active weight loss, but total cholesterol matters less than particle size and triglyceride ratios. Most studies show improvements in these advanced markers within 6-12 months.

What about the Mediterranean diet being ‘healthier’?

The Mediterranean diet shares many keto principles: emphasis on vegetables, fish, and olive oil. The main difference is carb sources – keto simply restricts grains and sugars more strictly while achieving similar cardiovascular benefits.

Should people with heart disease try keto?

Those with existing cardiovascular conditions should consult a specialist. Emerging research suggests keto may help manage metabolic syndrome, but abrupt dietary changes require medical supervision for high-risk individuals.

The Bottom Line

Current evidence contradicts the claim that ketogenic diets inherently harm heart health. For most people, reducing refined carbohydrates while increasing nutrient-dense fats improves lipid profiles and other risk factors. If you’d rather not do the macro maths yourself, the Keto Dieting app does it for you on Google Play and the App Store.

Educational only — not medical advice. This article is for general information. Speak to your GP before changing your diet, especially if you have type 1 or type 2 diabetes, kidney or liver disease, are pregnant or breastfeeding, or take medication for blood pressure, cholesterol, or blood glucose.

References

Kosinski C, Jornayvaz FR (2017). Effects of Ketogenic Diets on Cardiovascular Risk Factors: Evidence from Animal and Human Studies. Nutrients. https://doi.org/10.3390/nu9050517
Volek JS, Phinney SD, Forsythe CE, et al. (2008). Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet. Lipids. https://doi.org/10.1007/s11745-008-3274-2