Low carb, high fat diets, also called keto diets, have been gaining popularity as a quick way to lose weight.1 It involves consuming very low levels of carbohydrates, like bread, rice, pasta, and other grains, and high levels of fat, to induce the body into a ‘ketogenic’ state, using fats instead of carbohydrates as the primary energy source.
However, a recent study by Dr. Iulia Iatan, MD, PhD, and physician scientist at the Healthy Heart Program and Centre for Heart Lung Innovation and a postdoctoral fellow under the supervision of Dr. Liam Brunham, showed that a keto-like diet may be associated with increased risk of cardiovascular events such as chest pain, blocked arteries, heart attack, and stroke. Dr. Iatan used data from the UK Biobank, and identified 305 individuals who reported consuming less than 25% of daily calories from carbohydrates, and more than 45% of calories from fats. This is in contrast with strict keto diets that consist of less than 10% carbohydrates and 60-80% in fats.
Compared to individuals who report a more balanced diet, those on a keto-like diet had higher levels of LDL cholesterol, or “bad” cholesterol, which is a known risk factor for heart disease. After more than 10 years of follow up, 9.8% of people on a keto-like diet experienced a new cardiac event, such as artery blockage, heart attack, stroke and peripheral arterial disease, compared to 4.3% of those on a standard diet, representing more than a doubling of cardiovascular risk.
However, not everyone responds to these diets in the same way, and the data relied on an individual’s self-report of their dietary patterns at one point in time, which does not capture information about dietary changes over time. As an observational study, these findings cannot definitively prove that keto-like diets directly cause cardiovascular disease, but highlights the need for further research to understand the risks and benefits of these diets.