Built on Facts

Over this past semester I’ve discovered something unfortunate. If a person doesn’t get much exercise, snacks when bored, and shops when hungry, that person will tend to gain weight. That person is of course me, and so I’m going to try to do something about it. It’s by no means a new year’s resolution, I’ve been aware of the problem for several months now. And fortunately we’re early in the game yet. My BMI is roughly 25.5, which is just a hair into the “overweight” range. Some of you might be in the same boat, so we might be able to do some thinking about how to best put ourselves where we want.

How to go about losing weight? It’s no secret, the method is very easy. Carrying out the plan is not so easy. Essentially it’s thermodynamics. You put energy in via your food, and use energy in life. Make the latter bigger than the former and you’ll lose weight because that used energy has to come from somewhere. That somewhere is the chemical energy inherent in your fat, assuming you haven’t done some lunatic crash diet that causes your body to pull from other storage sites like your muscles.

The trick is to maintain that negative calorie balance in a way that doesn’t leave you hungry and obsessing about food. My plan is to gradually boost my calories used via walking, jogging, and some weight lifting. I can bump down the calories taken in via replacing less healthy food with things which are filling without being packed with calories.

Just how much is a calorie anyway? Officially in physics it’s the energy which raises one gram of water by one degree Celsius. As it happens, this is 4.18 joules. But complicating matters is the fact that food calories are designated differently, and in fact one food calorie is equal to 1000 regular calories. Intro physics textbooks tell you that the difference is that food calories are capitalized – something like “This cheeseburger has 1200 Calories, or 1,200,000 calories.” In practice I’ve rarely seen this done with any consistency. This is why physics usually just sticks to joules, and in fact why internationally food energy content is actually given in joules as well.

This definition does unfortunately show how one clever weight loss scheme doesn’t work. The idea is to eat all your food cold. Your body will have to spend energy to warm up the food, thus burning some of the calories (or Calories) that you ate. And it’s true. The problem is that if your cold burger weighs some fraction of a kilogram and has to be warmed 10 degrees (or whatever), you’re talking about a few thousand calories – which is just a few actual Calories. So in theory it would help, but I don’t think cold food is worth that pitiful improvement.

Too bad typing isn’t an aerobic activity.

Oh yes, and a minor unrelated milestone! Yesterday we had our 2000th comment here, and I’m immensely grateful for the wonderful and thoughtful quality of all of your commentary. Both the regulars and the occasional visitors have made this blog much better than it ever could otherwise have been. Thanks all!

Comments

#1 MPL
December 29, 2008

My advice, from my own experience is to do two things: exercise habitually, and keep a food journal. You don’t have to be militant about the calories. Just knowing that you have to go get your notebook and a pen cuts down on “snacking while bored”, and facing the list of what you ate motivates you to eat better.
#2 andyb
December 29, 2008

“Too bad typing isn’t an aerobic activity.”
You type so fast that it is anaerobic? You get stitch?

I recall reading that 3 hours extreme concentration burns the same as 15 mins running. Wish I could recall the reference…
#3 Uncle Al
December 29, 2008

UVic Commons cafeteria – eat all you want, dread the next meal. Monday, spaghetti sauce (slurry). Thursday, slurry with the fringe on top. Salmon possibly scraped up from stream beds after mating. The lettuce was near lethal (Campylobacter). 2 lbs/week weight loss no sweat.

One can more pleasantly patronize the U/Manitoba Servery. Food is delicious, abundant, and inexpensive but three meals/day won’t keep you alive through the winter. (Their potato salad is to die for – as good as the best NYC delicatessan.)
#4 bigjohn756
December 29, 2008

If you are getting fat DO NOT WAIT to work hard to lose. Once you become obese it is much more difficult to lose; plus, you have more to lose. I can attest to this personally. Yay! Anecdotal evidence…QED.
#5 Carl Brannen
December 29, 2008

Now I’m quite fat, back when I was a grad student I didn’t own a car and used a bicycle to get around. I was skinny and had those muscular bike legs. So sell your car and get a place a good distance from campus.

As far as bad food making you fat, my experience in blue collar jobs where one gets good exercise is that it is impossible to keep the weight on while working hard. Back when I didn’t have a car, I bought a dozen donuts on the way to work each morning and ate the majority of them for breakfast (well, my second breakfast) each morning. I cleaned my plate at lunch and dinner and I still was quite thin.

You might consider taking a summer job doing something manly. These sorts of things make a wonderful counterpoint to intellectual work and are very satisfying in many ways. My only advice is that as the muscle builds up, youth tends to think that they are indestructible and ruin their backs. Older blue collar workers are tough as nails but typically consume an amazing amount of asprin each day due to mistakes made years ago. It’s very difficult to reason with young blue collar types about being careful on the job to avoid back injury. I tell them that the worst part of over stressing your back is that sex would become painful.
#6 natural cynic
December 30, 2008

That somewhere is the chemical energy inherent in your fat, assuming you haven’t done some lunatic crash diet that causes your body to pull from other storage sites like your muscles.

In every study [I have seen] showing significant weight loss using a combination of exercise and/or dietary restriction, there is always a loss of muscle. The proportion of muscle to fat lost depends on how much strength training you do. Doing more strength work will keep more muscle, however it will take you more time to lose a given amount of fat since the Calories [or kilojoules] that you can expend doing aerobic activities in a given amount of time is greater than the number of calories that can be expended in any strength training program. So, do a mix.
#7 Nathan Williams
December 30, 2008

Go read “Good Calories, Bad Calories”, if for no other reason than to learn more about the calorie-balance issue (and how little we really know about human nutrition). Short version: the presence or absence of food, as well as its composition, affects your metabolic rate, so the “thermodynamic” method of weight loss doesn’t work very well.
#8 Chris
December 30, 2008

I’ve had good luck with the Wii fit, although I need to get back into a routine.
#9 JimFiore
December 30, 2008

I advocate distance running as an effective, efficient, and inexpensive means of maintaining health and weight control. It’s probably 50% more time efficient than walking for most people, requires hardly any equipment, and can be done in most places at most times, alone or in groups.

Here’s a decent equation to determine Caloric expenditure for typical individuals across a range of paces:

Calories Burned = .7 * W * D
Where W = weight in pounds
D = distance traveled (level ground) in miles
So your average 140 pounder burns about 100 Cals per mile run. Over the course of several months get yourself up to 30 miles/week and you’ll start seeing (and feeling) a difference.
#10 Peter
December 30, 2008

>>Essentially it’s thermodynamics. You put energy in via your food, and use energy in life. Make the latter bigger than the former and you’ll lose weight<<

True in a way but very misleading. There is a reason dieting is an uphill battle….

The problem is the “put energy in” part depends highly on the absorption efficiency of the digestive system. Most of us eat so much we are excreting, not asbsobing, many of the calories eaten. If you try to reduce calorie intake by simply reducing the food eaten, the body just gets better at absorbing the nutrients from the little food you do allow yourself. Until you have reduced intake to the point you are actually “starving” ie EATING less than you burn, there is little weight loss. This method is 1) uncomfortable in as you will be continually hungry, and 2) difficult to do in a healthy way where you do not miss essential nutrients as well.

Exercise, on the other hand works but not just by directly burning calories – activity tricks the body into ABSORBING and STORING fewer calories. This is a hold over from our evolutiion – our ancestors were active during times of plenty (sping and summer) and they did not need to store fat then, but were less active in fall and winter and at that point needed to conserve and store fat. Our body has a innate natural response to being sedentary – store fat.

So eat healthy and ramp up the exercise. Your body will move the food through faster and absorb fewer calories and it will break down and remove fat which is hindering your movement. (ie slim those abs) Since you will trade fat for muscle which is denser you may lose more in inches than in pounds but you will be healthier at any body weight with exercise than at that same weight with little exercise.
#11 Rumford
January 16, 2009

What you call thermodynamics is the first law. The first law never operates in the absence of the second law which says that all (real) processes are inefficient. So you want a diet that gives you reduced efficiency (with respect to fat storage). People who have good success with low carbohydrate diets says that they get more weight loss per calorie with that diet. They also say they eat less which may be part of it (not the thermodynamics part). Anyway, do the experiment. And low carbohydrate diets have always been attacked by professional dietitians and doctors so how bad could they be.

The definition of a calorie (or a kcal) in nutrition is not what you say it is. It is the heat of complete combustion of food (it is the energy of a process not a thing). But humans don’t necessarily carry out only complete combustion, they make cell material, DNA, etc. and different people on different diets operate at different efficiencies.

Try: http://www.tbiomed.com/content/pdf/1742-4682-4-27.pdf