Protein is the queen of macronutrients

Protein does more than blunt your appetite and speed up your metabolism. It also helps you maintain muscle while losing fat. For example, a University of Illinois study published in 2005 took a group of middle-aged women and split them into four groups. Two groups had higher-protein diets with few carbs, and two ate lower-protein meals with higher carbs. One group from each side exercised (a combination of strength training and walking) , while the others just changed their diets without exercising. The proteinplus-exercise group lost the most weight (22 pounds, on average) , and retained all but 1 pound of their muscle mass. Conversely, the carbs-plus-exercise group lost an average of 15 pounds, which included 2 pounds of muscle. Even more remarkable was that the higher-protein exercisers lost 11 pounds of middle-body fat versus 7 pounds for their carb-eating counterparts. Higher-protein diets seem to work regardless of the relative amounts of fat and carbohydrate. I 've seen higher protein produce better results in high-fat and low-fat diets, and in diets relatively high or low in carbs. Protein is to diets what black is to fashion: it makes everyone thinner. That leaves us in a position to choose our own combination of carbs and fat. It's safe to say that some amount of each is important. Since fats are crucial for the development and proper function of your hormones, and since your body can't make certain types of fats and thus needs to get them from your diet, a low-fat approach makes little sense. Conversely, I don't think a low-carb approach would be in your best interest, either, unless you have diabetes or a specific medical condition that requires such a diet. Alwyn's workouts require a lot of energy, pulling glucose from your blood and glycogen from your muscles at the same time you're deliberately inducing damage in your muscle fibers and connective tissues. You need to replace that glycogen in your muscles, just as you need to give your body protein to repair your working parts. You could accomplish both goals with a low-carb diet, but it's not the easiest, most direct, or most convenient way to do it. I'm deliberately hedging with my language here, because there simply is no settled approach that works for everybody. If I were your doctor and knew you were diabetic, of course I'd give you a low-carb plan, and concede that your muscles will have to make do without a large and constant supply of readily accessible sugar. If you were extremely overweight, I'd probably make the same recommendation. But if there were a compelling reason to design a low-fat and/or low-protein plan (kidney disease, for example) , we could do that as well. But in the absence of any specific and urgent reason to limit carbs or fat, the path of least resistance leads to balanced macronutrients. Once you brush aside ideology, the balanced-macro strategy ensures you get plenty of everything without too much of anything. Allow me one last argument: My friend Susan Kleiner, R.D., Ph.D., is a sports nutritionist in Seattle who works with elite athletes at every level, along with nonathletes. She's always been someone who combined current science with the most practical applications to get the best results for her clients. I 've never heard her proselytize for any particular dietary philosophy. Her latest book is called The Good Mood Diet, and in it she recommends a specific macronutrient ratio: 40/30/30. I asked her why she did that, and why she chose the one she did. "A diet with less than 40 percent carbs is depressing-literally. Forty percent is also better for fat loss," she told me. "A diet with less than 25 to 30 percent fat lowers coping skills and raises anxiety, anger, and hostility levels. " She went on to explain how she ended up at 30 percent protein, which turns out to be roughly the same calculation we use-2 grams of protein per kilogram (2.2 pounds) of body weight per day comes out to about 30 percent of calories for a typical woman eating the typical amount of food we recommend. Protein improves mood because of tryptophan, an amino acid you've probably heard of. (It played a role in a memorable episode of Seinfeld. Jerry, Elaine, and George feed tryptophan-rich turkey breast to one of Jerry's girlfriends so she 'll doze off and they can play with the vintage toys she 's collected but won't let any of them touch when she 's awake.) To sum up, the bottom line on macro nutrients is really a lot more straightforward than many nutrition experts make it seem. You need some of each, and given the fact we modern humans have the luxury to choose our own proportions, the best choice is a roughly equal mix. Too much of one thing means too little of something else, and each imbalance presents its own set of problems. But the most underrated reason for choosing balance is the one that probably matters most for long-term success: It's easier. So that's how we came up with the structure of the meal plan. In the next chapter, I'll talk about the specifics. Good Nutrition: Simple Versus Simplistic IF EVERYTHING my coauthors and I recommend were to be summed up in three steps, it's hard to go wrong with these: • Metabolism • Anerobic exercise • Nutritional consistency Conveniently, they give us a nice, easy-to-remember acronym -MAN (as in Lift Like a ... ). I 've talked already about the importance of maintaining or even increasing your metabolic rate; it's the key to weight control without a lifetime of deprivation. And you know how I feel about anaerobic exercise. A base of endurance is important-if you can't walk at a brisk pace for a half-hour without stopping for defibrillation, or ride a bike for a couple hours at a leisurely pace with your friends ... well, you need to fix that. The human body, as I've said, is designed to walk long distances on foot, and if you can't even manage relatively short distances, you're in trouble. So I'm not by any means disparaging the need for some endurance capability. My goal is to promote anaerobic exercise as not only the ticket to a better body now-the subject of this book, if that's not clear-but also the key to lifelong strength and mobility. You don't want to get to the point where you can't get out of a chair unassisted, or walk up a flight of stairs, or do a short little hop over some puddle of nastiness on the sidewalk. I know it seems absurd to worry about those things now, but when you're eighty or ninety, anaerobic fitness will be the difference between a nursing home and that worldwide cruise you can finally afford. This chapter is about the N: nutritional consistency. Once you separate nutrition science and practice from the preconceived notions that often drive them, what you're left with is the need to be nutritionally consistent-to eat the best foods, avoid the worst ones, practice moderation, avoid long stretches without any food at all, and, most of all, to employ all these habits almost all the time. It's easier than you think, once you know the basics.