Tuesday, August 11, 2009

Fatness -- Let's Do Some Math

Why are Americans a bunch of fatasses? Let's do some math.

Take a typical fast food meal:

Big Mac: 540 calories
Large Fries: 500 calories
Medium Coke Classic: 240 calories
Total = 1260 calories

The canonical 2000 calorie diet is only a rough estimate, one that is within about 10% accuracy for a male of my age and height, but may be very wrong for other people. In fact, all caloric intake estimates are imperfect, but you need to take into account factors like age, weight, gender, and rough activity level as this about.com calculator does. (And remember, that calculator is showing what you need to maintain your current levels, not slim down.) My wife, for example, should be eating about 400 fewer calories per day than me.

If we don't even account for the problems of empty calories (low nutrition, highly processed food that may impede metabolic reactions needed to properly consume the calories), water retention from high sodium foods, the fact that carbohydrates are burned easily and therefore preempt your body's need to draw from fat reserves, and other more subtle barriers to weight loss (and, more importantly, cardiovascular health and athletic muscle toning), we can see the roots of the problem from straight-up calorie math.

1260 calories is more than half the RDA for someone like me (a 200lb, 6 foot, 35 year old male). If all three meals Americans are eating each day are around the 1000 calorie mark, we're talking approx. 3000 calories or about 750-1000 extra calories a day for someone like myself. (And if you're doing the two Big Mac thing, and adding a 250 calorie baked apple pie, that's another 750 calories in one meal.)

I've been watching the readouts on the machines as I've been hitting the gym, and by way of example someone my size, weight, and age doing a moderate (level 5) cardio routine on the StairMaster is burning about 10cal/minute.

750 excess calories / 10cal/minute = 75 minutes

So, if I'm averaging 3000 calories a day, and my break-even estimate is 2250 calories, I'm at least 750 calories over break-even -- which means an hour and fifteen minutes of uninterrupted StairMaster workout just to break even. Most people who say that they are "relatively active" and are referring to less than an hour of cumulative strenuous walking, stair climbing, and similar activity during the day are fooling themselves. "But I walk a lot" perhaps applies to active people in New York City who may average two hours of fast walking per day or San Franciscans who pound the hills at reasonbly high speeds an hour a day (but even that's still going to be break even at best if it's not coupled with caloric moderation), but not really to anyone who just happens to have to walk during the day because their refrigerator isn't sitting right beside their TV.

The reason so many people are heavy is quite clear: easy access to high calorie foods, combined with the prevalence of sedentary post-industrial workplaces, make for people who eating far more calories than they'll reasonably burn in a day. This seems like common sense, but as the saying goes: sometimes common sense ain't so common.


Max said...

Fat is the candle in which carbohydrates burn. The obverse of your post is where I found myself for a long time, today included - not eating enough calories for the work being done.

wake: 7am, breakfast of 1/2c oatmeal, 1tbsp flaxseed, 2tbsp whey protein, 1 tbsp almond butter, coffee with whey protein and almond milk = 500 calories.

2 hour run, 13 miles - ~2,000 calories
On run consumed 150 calories of sport drink
Post run consumed 275 calorie sport recovery drink

coffee, whey, almond milk - 175 calories

missed lunch, at client - ate a larabar, 190 calories

Now I'm supposed to go for workout #2, a one hour swim. Scheduling has made that impossible, but I'm doing a triple workout tomorrow and I've moved my double swim workout to Sunday so I'll make it up.

But clearly I am way short on calories for the day. This means my body is going to store fat in reaction to the huge shortage. I'm going to eat a normal dinner of 500-1,000 calories but the damage has already been done and I am low for the day.

You must feed the beast if you're going to work the beast. And you're right, Americans have easy access to empty calorie-dense foods and they don't move much. But for those of us who move a lot, getting enough of the right calories can be even harder. I don't eat fast food, I get my calories from fresh colorful vegetables and lean meats, which are damn near impossible to find on-demand even in LA.

Most restaurants from low to high end serve a huge quantity of starchy carbs and a big slab of trans-fat rich protein (dark meats). This is no way to lose weight, either.

LHOOQtius ov Borg said...

Most people won't find themselves in Max's enviable position of being fit enough to train for a major triathlon.

But what he says (eating too little causing you body to store fat in response to the shortage) is why starvation / crash diets don't work. There is a physiological reason why people say you need to lose weight slowly and steadily.