Learn the Not-so-Simple Math of Energy Intake and Output




Counting calories as a means of managing weight has waxed and waned in popularity over several generations. Our grandmothers might have used saccharine in the 1950s as a way to stave off pounds, followed in subsequent decades by aspartame (Equal/NutraSweet) and sucralose (Splenda). Along the way Grandpa started counting his calories too, perhaps in response to fewer hairs on his head. A thousand different iterations of diet plans and programs have been promoted – high protein diets, grapefruit and cabbage diets, lemon-water fasting diets, to name a few.

Objective analysis shows us that weight management success boils down to calories. It really is a matter of what you take in – food and drink – versus what you put out, the expenditure side of the equation.

The easy but false analogy is putting gas in a car. But humans don’t all roll off one assembly line, nor are we driven on the same roads in identical conditions. We burn calories in different ways – while active, at rest, even in the process of eating and digestion. Take a few moments to understand this. It can make a big fat difference in how effectively you manage your weight.

The treadmill readout is wrong

There’s a particularly disheartening number that hits anyone engaged in regular machine-based cardiovascular activity, such as a treadmill, stationary bike or elliptical machine. It’s the calories-used digital readout. For example, from 20 minutes of running at a 9 minutes-per-mile pace, a 180 pound man will burn somewhere around 300 calories. After his workout, our robust exerciser might happen upon a medium-size bagel in the office lunchroom, slather on the vegetable cream cheese, and basically re-ingest 300 new calories in about two minutes.

One step forward, one step back? Fortunately, not exactly. No commercial treadmill is calibrated to very specific, individual differences, and every manufacturer uses different proprietary calculations on their machines. So odds are he might have burned off a bit more than 300 calories.

But the biggest under-calculation of caloric expenditure from exercise is found in something called EPOC, excess post-exercise oxygen consumption. This accounts for the raised metabolism after the trainee exits the equipment or ceases other forms of exercise. Some studies suggest this effect lasts as long as 38 hours, however, its effect is highest for an hour or two after exercise is completed.

Very important to note: the level of exercise intensity increases this effect considerably. Also, there can be a greater EPOC effect from anaerobic activity, resistance training, than aerobic exercise. For more on exercise intensity, check how the Mayo Clinic defines and outlines it.

Surprisingly, the National Council on Strength and Fitness, a fitness training and certification organization, encourages individuals to think outside of the gym for calorie-burning activities. They note that the caloric burn in a training session will range between 200 and 400 calories, which does not sufficiently create weight loss for most people. But if the trainee also walks a lot, or does housework, gardening or plays actively with children and pets, that burn rate can be elevated for many more hours during the week.

Eat and nap – both require energy

The news gets better: you actually use calories when eating. Called TEF, the Thermal Effect of Food (a.k.a., thermogenesis), it accounts for the process of chewing, swallowing, digestion and absorption. For some people, the effect includes sweating while eating – good for burning calories, perhaps compromising in social situations. It’s also a great argument for unprocessed foods: your body spends more energy and time digesting whole-grain breads than a cake-like slice of Wonder Bread, which has the slower-digesting fiber removed. Healthy snacks between meals also stimulate TEF.

The factor underlying all individual’s caloric expenditure is the BMR, basal metabolic rate. This number reflects how many calories your body burns just to exist, to keep you alive. A 180-pound man typically burns about 85 calories per hour, or about 2000 calories per day. This number can be significantly increased, however, by increasing the ratio of muscle to fat. Why? Every pound of muscle requires 50-70 calories per day, while each pound of fat only consumes 3 calories in a 24 period. Yet another reason strength training is beneficial to overall health. Big muscles are not just a matter of looking good.

So the next time you see a bodybuilder napping, keep in mind he or she is still burning a lot of calories. Perhaps it can be your motivation to train harder yourself – it’s a lot better for you than your grandmother’s Tab soda.