The big fat story

Olive oil is at the midpoint of healthy oils. Photo

Recently I posted my eating philosophy. It is what ,after two decades of studying, practicing and thinking about nutrition, I eat myself. I got a great comment asking about what I think about fat intake, and if it's more important to limit fat or carbohydrate. Good question - thanks Margo!

First, let's talk about fat. I'm a fan of Udo Erasmus, the author of Fats That Heal, Fats That Kill. He's been a leading lipid researcher and thinker for decades, and I like the way he thinks about the issue.

Erasmus lead the charge, I'd say, in defining quality when it comes to fats. Americans eat too many omega-6 fatty acids, found in processed foods and some vegetable oils, and don't get enough omega-3 fatty acids, found in in fatty fish, flax and other vegetables oils.

I think the Mediterranean diet folks have it right on healthy oils, too. Oldways Preservation Trust is a great resource for delicious Mediterranean eating. Here's a nice overview from Harvard School of Public Health - I agree with this piece that the type of fat you eat is perhaps more important than how much you eat. Or, both quantity and quality are important.

So, back to Margo's question of what is more important to limit, fat or carbohydrate. Sorry Margo, but the answer is: it depends on your individual needs, but in today's nutrition environment, probably both.

After reviewing the literature on calorie distribution, the Dietary Reference Intake group of the Institute of Medicine (IOM) set the following acceptable ranges for healthy intake:

• Fat: 20-35% of calories
• Carbohydrate: 45-65% of calories
• Protein: 10-35% of calories

You will find a wide variety of recommendations among nutrition experts with differing points of view. The Dean Ornish camp have successfully treated cardiac patients with a 20% fat vegan regimen, while Erasmus recommends 50% fat for individuals who are ill. Some low-carb regimens go as low as 10% carb, and the WHO sets the upper carb limit at 75% of calories. Just know that if you go much higher or lower than the IOM recommendations, an exhaustive review of the current science is betting against you.

But for all of us, quality matters. Choose as much quality fat (unsaturated and monounsaturated fats, which mostly come from plants, and omega-3s found in oily fish, flax seed and other sources) as you can, and reduce low-quality fats (saturated fats which mostly come from animal sources, and omega-6s). As for carbohydrates, choose quality carbohydrates (nutrient-rich fruits and vegetables, and a little whole grain) while steering away from low-quality carbohydrates (sugar, white flour and most processed cereals, crackers and chips).