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Which Is Worse: Saturated Fat or Added Sugar?

01/20/2016 05:50 pm ET

Which-is-Worse games can be silly, but the fat vs. sugar question might have real health implications. 

The 2015-2020 Dietary Guidelines for Americans target both saturated fats and added sugars as nutrients to limit and seem to give them equal weight: "Consume less than 10 percent of calories per day from added sugars" and also: "Consume less than 10 percent of calories per day from saturated fats", they advise.

A new paper by James DiNicolantonio, Sean Lucan and James O'Keefe in the journal Progress in Cardiovascular Diseases examines the evidence and comes to a very different conclusion.

One in 6 Americans die of coronary heart disease. Although cholesterol plaques narrow arteries, the cholesterol in our food is not the main culprit in atherosclerosis. Our body produces most of its cholesterol, but what we eat affects cholesterol too. The theory that saturated fats increase blood cholesterol was developed by Ancel Keys, and was adopted in government guidelines. Later on, researchers found that not all cholesterol is the same. How cholesterol is packaged matters, and we came to understand that there's good (HDL) and bad (LDL) cholesterol, and that total cholesterol doesn't predict heart disease as much as the ratio between these different molecules.

Some saturated fats elevate bad cholesterol, others have no effect, and others actually increase good cholesterol, and fats in foods never come in isolation - they're always a mixture. While some foods high in saturated fats, such as processed meats, are connected to heart disease, other high saturated fat foods (such as dairy) have no such effect.

Moreover, since the eat-less-saturated-fat advice has been around for decades, there has been plenty of time to put it to the test. This new article cites several meta-analyses of randomized trials that did not find a connection between saturated fats and heart disease or overall death rates.

Now they looked at sugar. Added sugar, especially fructose, which is a component of table sugar, high fructose corn syrup, and most caloric sweeteners, tends to increase total cholesterol and LDL (bad cholesterol), lower HDL (the good cholesterol) and raise triglycerides.

And here's an instructive comparison mentioned in the article: to match the damaging cholesterol influences of the added sugar in a typical diet one would have to eat 40 percent of daily calories in saturated fat (which is highly unusual -- most people eat only about 10 percent).

Sugar's negative heart effects don't end with cholesterol. Diets high in added sugar are linked with insulin resistance, impaired glucose tolerance, changes in platelet function, fatty liver disease, diabetes and obesity, all linked to heart disease.

It's often hard to pick a winner to Which-is-Worse questions, but the authors argue that excess added sugars are unhealthier.

When it comes to highly processed foods, many of them are high in one or both, which makes this question relevant, but there's a better response to it.

If you choose whole foods, you shouldn't have much of a dilemma. Ripe fruit are very sweet, have sugar, most of it fructose, but they are associated with good health, and lower risk of heart disease. The fats in plants are a mix of saturated and unsaturated fats, and while avocado and nuts have mostly unsaturated fats, even coconuts, which are mostly saturated fats, haven't been associated with disease.

As long as you eat mostly whole foods, mostly plants, you won't need to pick a lesser evil.

Dr. Ayala

This is a crosspost of my blog, Healthy Food & Healthy Living, where you can reach me at ayala@herbalwater.com.

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