I don't think the body has a preferred fuel. I don't think the body cares what it runs on assuming it's real, whole foods. I don't think animal fat is necessarily a healthier fuel than carbohydrate from sweet potatoes. I can tell you with absolute certainty that I STRONGLY believe carbs from fruits and tubers are FAR healthier than soybean and/or canola oil! With anything, it comes down to the food source, and every study seems to show that indigenous cultures, regardless of macronutrient breakdown, seem to be relatively free of modern disease. Kitavans that eat huge amounts of carbs and very little fat and protein don't seem to be any less healthy than Inuits eating almost nothing but fat and protein with nary a vegetable in sight.
The real killers seem to be grains, sugars, legumes, PUFA-oils and the like - you know, fake frankenfood crap.
Mark seems to prefer fat for fuel because of the sedentary nature of the modern human. You know what, if you're sitting on your butt all day at your desk, you're probably better off eating a fattier/lower carb diet because it's a little more stressful to process carbs than animal-based fats. Using that logic, you may age less on a low carb diet if you're very sedentary. For someone active, I believe the opposite to be true. Active people tend to suffer and have elevated cortisol on needlessly low-carb diets. I'm a modest weight lifter, and if I go low-carb too long I feel lousy, stressed and tired. Carbs make me feel better and less stressed, so I eat them regularly and in large amounts when I get the urge. The amazing thing is we naturally seem to cry out for the fuel we want. Sedentary people generally feel tired and "crash" eating high carb diets while gym rats and athletes tend to feel like crap eating low-carb.
The real key is eating what makes YOU feel best. Pair your food to your energy levels and that's the key to success. Don't look at it in terms of macronutrients. If you're feeling sluggish, add some carbs. Reach for an apple, some berries, a banana, a sweet potato - whatever. If you're crashing after lunch at work, dial down the carbohydrate and eat fattier meat. Don't stress over health - a sweet potato is just as good as a steak in terms of health. Eat the one that makes you feel best. The only thing I stress is to make sure you're getting adequate protein. 1 pound of meat on average is ~100g of protein. IMO, most of us should be aiming for at least that, with smaller sedentary women being able to get away with the 75-100g range.
Remember - humans are omnivores. We eat meat, vegetables, fruits and tubers. It's all good. Stay away from the extremes and try to include everything in there in some quantity.
Last edited by ChocoTaco369; 06-12-2012 at 02:16 PM.
Don't put your trust in anyone on this forum, including me. You are the key to your own success.