Low-fat diets have (thankfully) fallen out of fashion. But how much fat is too much? Nutrition Diva investigates
Today’s topic was inspired by an email from a listener, which I’ve quoted below in its entirety, for reasons that should be clear by the end of the episode. Tip: Click on the highlighted words to view previous Nutrition Diva episodes on those topics.
From what Katrina has outlined here, I think her diet is healthier than most! If anything, she’s a little ahead of the curve..
The field of nutrition has been gradually recovering from the misguided fat-phobia that—among other things—influenced the Institutes of Medicine’s recommendation that fat take up no more than 35% of your calories. In fact, in a recent email exchange with me, Walter Willett from the Harvard University School of Public Health suggested that getting up to 40% of one’s calories from healthy sources of fat would be perfectly acceptable—especially if those calories were replacing refined carbohydrates.
I’ve talked about the IOM’s recommendations before, in the context of similar discussion about how much protein one should eat. The guidelines allow for anywhere from 10% to 35% of calories as protein, which is a very broad range. For someone my size, 10% of calories would be a little over 50 grams of protein and 35% would be almost 200 grams! How can both be equally good for me?
The lower end of the range represents the minimum amount of protein your body needs to function. And although you don’t necessarily need more protein than that, I’ve discussed various advantages of higher-protein diets in previous episodes. But keep in mind that the IOM isn’t just looking at the effects of protein (or fat) in a vacuum. They’re also trying to consider how higher or lower intakes of one nutrient might affect the balance of other nutrients in the diet.
It’s a Zero Sum Game
Remember that the percentage of protein, fats, and carbohydrates always has to add up to 100%. If you decrease the percentage of one, the percentage of another will have to increase. Previous efforts on the part of the government and public health agencies to get us to avoid fat, for example, led to a dramatic increase in the amount of carbohydrates in the typical diet. With the benefit of hindsight, we can now see excessive carbohydrates (especially refined carbohydrates) are doing much more damage to our health than the fat they replaced.