Huffpost Healthy Living
The Blog

Featuring fresh takes and real-time analysis from HuffPost's signature lineup of contributors

Mark Hyman, MD Headshot

Fat Does Not Make You Fat

Posted: Updated:

If you’re feeling completely confused about whether you should cut fat from your diet, you are not alone.  But here's the bottom line: Fat does not make you fat or sick.  

So, why do so many people believe that fat is bad for you and causes heart attacks?  This all started in the Dr. Key’s Seven Countries Study decades ago that examined heart risk based on lifestyle and dietary habits.  He found that in the countries where people ate more fat -- especially saturated fat -- there were more cases of heart disease, and he concluded that the fat caused the disease.  But here’s the problem with this study: Correlation is not causation.  Just because both fat intake and heart disease were higher among the same population doesn’t mean the heart disease was caused by the fat consumption.  Here’s another way to look at it: Every day, you wake up and the sun comes up, but although these events happen at the same time, you waking up doesn't cause the sun to come up.  A study that observed this would show a 100 percent correlation between these two events, but it would be wrong to conclude that you caused the sun to rise.

Because of studies like this, we became sidetracked into believing that saturated fat causes heart disease.  But in fact, we are now learning that sugar is the true culprit, not fat.  A review of all the research on saturated fat published in the American Journal of Clinical Nutrition found there was no correlation between saturated fat and heart disease.  And a recent editorial in the British Journal of Medicine hammers home the same point and shatters the myth that fat causes obesity and heart disease.  Researchers have found that, while it’s true that lowering saturated fat in the diet may lower total cholesterol, it’s actually lowering the good kind of cholesterol, the light, fluffy, buoyant HDL that's not a problem.  When people eat less fat, they tend to eat more starch or sugar instead, and this actually increases their levels of dangerous cholesterol, the small, dense cholesterol that causes heart attacks.

In fact, studies show that 75 percent of people who end up in the emergency room with a heart attack have normal overall cholesterol levels.  What they do have is pre-diabetes or Type 2 diabetes.  So, what’s the conclusion here?  Eating a diet with good quality fat and protein prevents and even reverses diabetes and pre-diabetes (diabesity).  And eating sugar and refined carbs cause diabesity. 

So, I encourage you to look at the issue of fat and sugar in a totally different way.  Don’t cut out the fat; enjoy it! 

Eat good fats. Here are my favorite sources of fat:

  • Avocados
  • Nuts -- walnuts, almonds, pecans, macadamia nuts, but not peanuts (one recent study showed a handful of nuts a day reduced death from all causes by 20 percent)
  • Seeds -- pumpkin, sesame, chia, hemp
  • Fatty fish, including sardines, mackerel, herring, and wild salmon that are rich in omega-3 fats
  • Extra virgin olive oil (a large study showed that those who consumed 1 liter a week reduced heart attacks by 30 percent)  
  • Enjoy grass-fed or sustainably raised animal products (I recommend the Environmental Working Group's Meat Eater’s Guide to eating good quality animal products that are good for you and good for the planet). 
  • You can even eat saturated fat like extra virgin coconut butter, which is a great plant-based source of saturated fat that has many benefits.  It fuels your mitochondria, is anti-inflammatory, and it doesn't cause problems with your cholesterol.  In fact, it may help resolve them.  I have many diabetic patients whose health improves when I get them on diet that’s higher in fat. 

I was just talking to researchers from the Joslin Diabetes Center who told me that the low fat recommendations for diabetics promoted by the American Diabetic Association has in fact been harmful, bad advice making diabetes worse!  Their new research shows that diabetics should be switching to a diet that's about 30 percent fat, 30 percent protein, and about 40 percent low starch vegetables and fruits (carbohydrates).  That turns their previous advice on its head.

So here’s the take-home message: Fat doesn't make you fat.  Sugar makes you fat.  Eating good fats can actually help you stay healthy.  So, eat good quality fats and real, whole, fresh food, and don't worry about it.

Now, I'd like to hear from you.  Send in your comments and share your experiences.  How have you noticed fat and sugar affecting you?  What happened with your cholesterol when you changed your diet?  I encourage you to share this newsletter with your friends and family on Facebook and Twitter.  And submit your questions so that, next week, I may make a House Call to you. 

Mark Hyman, MD is a practicing physician, founder of The UltraWellness Center, a six-time New York Times bestselling author, and an international leader in the field of Functional Medicine. You can follow him on Twitter, connect with him on LinkedIn, watch his videos on YouTube, become a fan on Facebook, and subscribe to his newsletter.

For more by Mark Hyman, MD, click here.

For more on personal health, click here.

From Our Partners