Are you still confused about all the contradictory advice on fat and carbs? We have been told for decades that low-fat is best when it comes to our health. Turns out, that was pretty bad advice.
We now have even more evidence showing that fat certainly isn’t “bad,” and it is probably beneficial for our health. Carbohydrates, on the other hand, are trending toward the “bad” side and may need to be reduced.
Confused? I don’t blame you. Read on for more info.
First my usual disclaimer.
We do not eat fats and carbs. We eat food. A wonderful combination of macro- and micronutrients, including fat and carbs. Whole grain bread, farro, quinoa can all be labeled as carbs. So too, can bleached white bread, French fries, Cheetos, and cookies. They are all carbs, but I guarantee you they are not all the same for your health.
Grass-fed steak, wild salmon, and avocado can all be labeled as fat and protein. So too, can deep fried chicken, processed lunch meats and others. Do you see where I am going with this?
With that disclaimer in place, let’s talk about the new study released in the Lancet and presented at the European Society of cardiology Conference earlier this week. You may have already seen the headlines, “Low-fat Diet May Kill You!” “The Low-Fat, Low-Carb Question Has a New Answer.” And others. As usual, the truth is never as exciting as the headlines, but it is still worth exploring.
This trial followed over 135,000 subjects from 18 countries for over 7 years. Researchers recorded nutritional intake through standard questionnaires (which are subject to errors as I’ve mentioned before), and investigators followed the subjects, noting who died, who had heart attacks, strokes or heart failure.
The short answer is that the group with the highest intake of carbohydrates (77% of daily calories) had an increase in their risk of dying when compared to the group with the lowest intake of carbs (46%). Interestingly, their risk of dying from heart disease was not increased, but their overall risk of dying was increased. This was mostly driven by cancer, respiratory diseases and dementia.
Intake of fat, on the other hand, was associated with a lower risk of dying. This held true for saturated fat, monounsaturated fat and poly unsaturated fat. There was no significant change in the risk of cardiovascular disease, but again, total mortality was significantly improved.
What can we make of all this?
It is important to remember that this was an observational trial. It doesn’t prove anything. It shows a very interesting association, but there is no way to control for all the variables that could influence the outcome (as an aside, the same caveat applies to all the prior observational trials condemning saturated fat).
The subjects filled out a food intake questionnaire at the beginning of the study, but they were not followed over the seven years to see if their food intake changed. That can certainly introduce inconsistencies in the data.
Also, the study lacked many nutritional specifics. What kind of carbs were the subjects eating? Something tells me in the high carbohydrate group, it probably wasn’t sweet potatoes, buckwheat, quinoa, and amaranth. The higher the overall intake of carbs, the more likely their diet included poor quality carbs. Food quality matters.
Nonetheless, increasing carb intake seemed to go along with increasing risk of death. That association was clear. Conclusion #1, therefore, is to reduce our carb intake. My editorial is to reduce your low-quality carb intake, although that was not specifically studied.
Increasing fat intake, on the other hand, was associated with a reduced risk of death. The group eating 35% fat had a better survival than the group eating 10% or 18%. Importantly, increasing fat intake was not associated with a lower risk of cardiovascular disease. But it wasn’t associated with a higher risk of cardiovascular disease either. It was neutral to heart disease, and beneficial to overall mortality.
Picture your doctor telling you a pill won’t change your risk of heart disease, but will reduce your risk of dying. And it’s only side effects are enjoying it as you ingest it, it gives you energy and nutrients, and helps you feel full. Sounds like a pretty good pill to me! Sign me up. Only in this case, it wasn’t a pill. It was dietary fat.
Conclusion #2, therefore, is to not fear the fat. Adding fat can be a benefit, especially if (again, my editorial) it is high quality and helps you reduce your carb and overall caloric intake.
There is Another
Based on most social media headlines, one may think that this was the only PURE study. It turns out, there was another one.
The other PURE study involved the same group of individuals, but it investigated overall fruit, vegetable and legume intake. The researchers found that three-to-four servings per day of fruit, vegetables and legumes was associated with the greatest decreased risk of death.
Interestingly, adding more was of no further benefit, but eating less was a lower benefit. This likely did not get the same media attention as the low fat study since the benefits of eating fruit, vegetables and legumes is much less controversial, and not surprising at all.
Should anything change from these studies?
Yes and no.
Real-foods like veggies, fruits, beans, legumes, nuts and seeds are a great place to start for most people. Hopefully we already knew that.
Fear of fat should get squashed. Fat is not inherently dangerous. Hopefully we already knew that as well.
Concern for too many carbs should be a hot button issue. Hopefully we already knew that also!
What may change for some people is further increasing the fat (up to 40+% of daily calories) and animal sources in your diet, and further limiting the carbohydrate sources (down to 40% of calories). Go ahead and add fish, meat, chicken, eggs, milk, olives, olive oil, avocados and avocado oil to your diet. Especially if your diet is based on veggies, fruits, beans, legumes, nuts and seeds. The evidence supports it.
Be careful of over-generalizing these results. Many details are missing, and observational trials cannot control for all the important variables. But since this is the best evidence we have, we still should take note.
Will this be enough to change national nutritional guidelines? That seems unlikely. Bureaucracy is much slower to move than individual recommendations. On an individual basis, not many people follow national guidelines anyway. But guidelines do impact governmental programs (i.e. school lunches, etc.), so my hope is that they will take note and start to change with the tide.
Eat foods that make you happy. Eat foods that fit with your traditions. Just make sure you follow the concept of eating simply prepared, high-quality, real foods. Don’t over-do the carbs, and don’t underdo the fats. Start there and you are well on your way.
Interested in more information? Listen to my podcast, The Boundless Health Podcast here, read more of my blog here, learn about my book, Your Best Health Ever, here, or The Boundless Health Membership Program here. My goal is to provide helpful information through multiple avenues to make sure you get what you need to live Your Best Health Ever!
Thanks for reading
Bret Scher, MD FACC
Cardiologist, author, founder of Boundless Health