There’s a common assumption in the medical and nutrition world that a low carb, high fat diet, like a ketogenic diet, will automatically increase one’s risk for heart disease. However, it’s crucial for us to realize that this assumption is inaccurate and not supported by data.
In fact, it’s been well documented that low carb diets can help someone reverse type 2 diabetes and improve metabolic health, changes that dramatically lower one’s cardiac risk. Research and clinical experience supports that a properly formulated low-carb diet can help someone improve, rather than worsen, their heart health.
But many may wonder, how can this be true when I’ve heard that eating fat is bad for us and bad for our hearts?
A big problem comes from assuming that our bodies react the same way to a diet high in carbs + fat as we do to a diet LOW in carbs and high in fat. The truth is that our bodies react dramatically differently to those two versions of a high-fat diet.
How It Works
You see, when we eat lots of carbs, our body uses the carbs as fuel first. Therefore, we won’t burn the fat for energy, and we end up storing it as adipose or fat stores. But when we eat a very low carb diet, our bodies prefer to burn the fat for energy, and therefore there is much less left over to store as body fat. This is dramatically different from a high carb diet!
Studies also demonstrate that people eating a low carb, high fat diet naturally reduce their calories, thus eating less and losing weight seemingly without trying. But those eating high fat and high carb diets tend to eat more calories and gain weight.
So you can see how we can’t just refer to a “high fat diet” as if it is one thing. It makes a big difference if it is also a high carb or low carb diet.
The Main Contributors
Let’s review the main contributors to heart disease, and see how a low carb, high fat diet impacts them.
1- Blood pressure
One study demonstrated a ketogenic diet lowers blood pressure better than the DASH diet, the diet previously felt to be the best for blood pressure management. And others have shown safe and effective blood pressure lowering when starting a low carb, high fat diet that is similar to a low-fat diet.
2- Type 2 Diabetes
Numerous studies demonstrate the efficacy of low carb diets for treating and even reversing type 2 diabetes. Since diabetes is a major contributor to heart disease, reversing it will significantly improve one’s heart health.
3- Inflammation
Ketogenic diets have been shown to reduce many markers of inflammation, including the commonly used CRP.
4- Triglycerides and HDL cholesterol
Having low triglycerides and normal to mildly elevated HDL cholesterol levels are predictive markers of better heart health, likely because they occur with good metabolic health. Numerous studies demonstrate that ketogenic diets reliably help lower triglycerides and raise HDL, thus improving overall cardiac risk.
5- LDL cholesterol
Many assume that high fat diets raise LDL cholesterol. But again, that is not the case. Multiple studies demonstrate no net change in LDL on a ketogenic diet compared to a low fat diet. In fact, one analysis of multiple studies found a net reduction in LDL particles for those following a ketogenic diet.
Important to Note
However, there is a subset of individuals who can see a dramatic rise in their LDL cholesterol when following a ketogenic diet. These so-called Lean Mass Hyper Responders, have unique physiology that predisposes them to an increase in LDL. But it’s important to realize that these individuals are the minority, not the majority. And there’s even emerging evidence suggesting that elevated LDL may not place these individuals at a higher risk, although with much still to learn.
In Summary
The data does not support the assumption that low carb, high fat diets increase heart disease risk. In fact, many studies demonstrate overall improvement in most, if not all, cardiac risk factors. We need to stop assuming all high fat diets are the same, and realize the unique heart health-improving impact of low carb/high fat diets.
If you would like to learn more about the misperception and misunderstanding about ketosis and heart disease risk, please see the video links listed here:
Does Keto Cause Heart Disease?
Debunking a study claiming low carb diets cause heart disease
Analysis of a study demonstrating lowering of cardiac risk with low
carb diets
Thanks for reading,
Bret Scher MD FACC