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When my friends ask about nutrition, explaining fat is the very first thing I try to do.

Eating fat does not necessarily make you fat, nor is it in itself a bad at all. Many fats are among the best things for your brain and heart. At the same time, fat-free foods can quite easily be bullshit.

A pound of sugar is fat-free, after all, but has an insane calorific value. (110 per oz)

Sugar is 100% total carbs.

A ounce of feta cheese has plenty of fat, and less calories per ounce than zero-fat sugar (feta is 75 per oz).

Feta cheese is 75% fat, 20% protein, 5% total carbs.

Then I try to show them some fat-free products that nonetheless has immense amounts of sugar and calories.

I think that using this topic as a lead-in has been the most effective way to get my friends to change their diets and consider what they eat.

This is one reason I find Michael Pollan's work so interesting, like "Unhappy Meals": http://www.nytimes.com/2007/01/28/magazine/28nutritionism.t.... (advice: "Eat food. Not too much. Mostly plants.") and In Defense of Food: http://www.amazon.com/Defense-Food-Eaters-Manifesto/dp/01431... .

His basic point is that "food science" doesn't know very much, is heavily politicized, and that we don't really know on a deep level how food, food-like substances, supplements, and so forth work. The war on "fat," as you note, doesn't make much sense because it counts the "fat" from a Big Mac and the "fat" from almonds the same way, which makes little sense. It counts the "sugar" from strawberries and Pepsi the same way. This is, to put it lightly, stupid, and it makes people stupid, since most people hear marketing slogans or public service announcements or whatever and follow those.

Put another way, Pollan recommends looking at more of a systems-level view of food, instead of a purely components-based view.

I do know that some people have raised issues with his science.

Haven't heard too many complaints about his general takeaways though...

+1 recommended reading for "In Defense of Food". It's way outside my regular reading tastes (pop-ish science + nutrition related), but I enjoyed every moment of it, and it's definitely changed the way I think about eating.

Excellent points.

Bodybuilders know a lot about diet, especially in the context of controlling the body fat percentage - mostly because in their case, the diet must work, or else they lose the competition. They can't rely on the latest fad on Oprah's that may or may not actually work. So the stuff they do tends to have a solid reality-based backing.

Any bodybuilder will tell you that low-fat diets are bullshit. Carbs are probably more aggressive fat-builders than fat per se, mostly because carbs are absorbed quickly, while fats are absorbed more slowly.

It's interesting to see the convergence from various sources. E.g., some diets recommended by weightlifters for "maintenance" (only to preserve a certain physique), and the diet recommended by Ray Kurzweil on health and longevity grounds, are similar in that the recommended daily intake of macronutrients is 33% carbs, 33% fat, and 33% protein as percentage of calories, or roughly 2:1:2 in weight.

As a comparison, that's slightly more protein that most people normally eat, a heck of a lot less carbs than the average intake, and a fairly average level of fat intake. I actually did this; reducing carbs was hard at first, but I got used to it after a while. It's amazing just how high you can raise the total caloric intake, if you keep the macronutrients at 33/33/33 relative ratios, without starting to gain fat. I was eating over 3200 cal / day, with 3 hours of lifting weights / week as my only exercise, and I was neither gaining nor losing fat (but I was gaining muscle).

In my mind, there's no doubt: By far the easiest way (in terms of effort spent, hours in the gym spent, etc.) to lose fat is to reduce the total calories by reducing the carbs intake (don't bother with tweaking the fat intake), and lift weights either 2 or 3 times a week, between 30 and 60 minutes each. 2 x 30 is the minimum that produces results, 3 x 60 is the maximum that allows you to keep it up a long time without burning out.

Don't eat carbs below 25% of your daily caloric intake, or you'll start to feel pretty weak. In other words, reduce carbs, but don't be a carbs nazi.

EDIT: This message was edited several times.

I haven't read his stuff in a while, but in his book The 10% Solution For A Healthy Life, Kurzweil advocates 10% fat calories. Has he changed that?

Yes, the concern was that with only 10% fat you'd have to consume more carbs, which carries some risk of desensitizing the body to insulin. Not that fat is completely risk free, but consuming some healthy fat is better than eating lots and lots of carbs.

You should also tell them that fat and carbohydrates are basically interchangeable. The body can easily convert between them, so there is little point in limiting just one of them.

In fact eating fat will probably lead to less calories overall since fat gives an earlier feeling of fullness.

Fat also satiates the appetite. You tend to not overeat when you eat fatty food. Starches and sugars do not, you want more.

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