A reader writes:
I agree that just because someone is overweight doesn’t necessarily mean they eat to much…however it does mean they don’t exercise
I’m sure that you probably don’t mean this to be taken as a technical statement, but . . . it’s . . . not . . . true. It comes across as a diss to people who are overweight. It sounds like a cavalier dismissal of their situation, including whatever efforts at exercise they may be making. It would be better to make the statement in a more qualified manner, for as it stands it is subject to a number of criticisms:
1) Exercise is not a binary phenomena. People don’t fall into two classes of “those who exercise” and “those who don’t exercise” with no further relevant distinctions. Physical activity is something that exists on a continuum, and merely falling into the “does exercise” category is not a guaranteed cure for the problem of overweight.
2) Even falling into the category of “does a lot of exercise” isn’t a guarantee of losing body fat. Look at professional football players. Those guys tend to get a lot of exercise, but they also tend to have a lot of body fat (because they consume more calories in order to simultaneously [a] keeping doing the exercise and [b] keep their bodies at the homeostatic weight points they want to remain at).
3) Depending on the metabolic state one is in, doing exercise can increase the appetite one has, as the body tries to stay at its homeostatic weight point and responds by increasing appetite as physical activity increases. If you just add some exercise without addressing dietary considerations, this is likely what will happen to you: You’ll just eat more. (Paradoxically, there are also states–which dieters can exploit–where the body decreases appetite as exercise increases. The point is simply that not everyone who exercises is going to lose weight.)
4) Even when one is in high weight loss mode, exercise is rarely if ever a sufficient condition for that weight loss. Exercise tends not to add that much to the calories we burn each day. Consider:
A 6’0″, 200 lb., 30 year old man is likely to have a Basal Metabolic Rate (BMR) of 2019 calories per day (BMR Calculator). This is the number of calories he needs just to lay in bed, without adding any physical activity. If you add his daily work duties to this (let’s say he does office work), you might get the number up to 2500 calories.
Let’s just stick with his BMR for the moment, though. How much physical activity would he need in order for exercise to equal what he needs to just keep the lights on and the machinery working? Well, he’d need to generate another 2019 of calorie burning through exercise. How much is that? It depends on the exercise he does, but let’s take a common one that is easily within the reach of almost all dieters: walking. If a person of his weight walks briskly for half an hour, he will burn approximately 220 calories. This means that in order for his exercise-based calories to equal his BMR-based calories, he would have to walk briskly for 4.6 hours a day. (NOTE: There are some quibbles to make with these numbers, but they don’t affect the scale of exercise required, so we can stick with these numbers for purposes of showing the principle.)
Very few people are able to make that kind of exercise investment, and so exercise rarely plays as big a role in calorie expenditure as BMR. The result is that diet rather than exercise tends to be the most important factor in weight loss. In order to effectively lose weight, dietary change is what is needed. Exercise is an important adjunct to this (otherwise I wouldn’t do five miles of aerobic power walking per day, plus weight training), but exercise by itself is not the solution to weight problems for most people. It’s not even the major factor. Diet is more important.
6) Exercise also is not a necessary condition for weight loss. A few years ago I was dealing with a significant weight problem and lost almost seventy pounds without doing any exercise, simply by making a dietary change.
Diet rather than exercise tends to be the dominant factor in weight loss. The trick is, how to take in less calories than you expend without being eaten alive by hunger–a subject I imagine we’ll end up discussing in the fullness of time.
Well said, and I do take back the sweeping generalization I made. I guess losing wieght differs from one person to the next. I lost 50 pounds in two months a few years ago, because 1.) I ran at least thirty minutes every day, and 2.) I followed the atkins/south beach Philosophy, limiting simple Carbs and eating high quality protein including fish, chicken and soy.
Also, eating a diet high in fiber keeps you full longer and thus it’s easy to limit your daily calorie intake without dieing of hunger. A bowl of craked wheat, or oatmeal in the morning keeps me full for at least 5 hours..
I also will note that not everbody can just “run” thirty minutes a day, most people would need to start out walking for months before starting a running program. I burn at least 450 calories when I ran for 30 minutes, but if I walked for 30 minutes I’d only only burn about 220 calories.
I ran track and cross country in high school 4 years ago, and 2 years after I gained 50 pounds, so running isn’t that difficult or harmful for me- I used to it. But most people cannot just start running and, as a result it’s harder to lose weight just walking.
Jimmy,
One thing I remember seeing in the news is that children in the US are much more overweight than in past generations. If your explanation of weight gain is true, and it may very well be, how does one also explain the much greater incidence of obesity among children (as well as adults) than in past generations? If the problem of obesity is primary biological, why would we see such a large increase in the percentage of obesity in today’s generations?
Perhaps it is not only a function of how many calories one eats, but also what kinds of calories one eats. Does a person gain more weight from eating 500 calories worth of donuts than they would from eating 500 calories worth of fruit, for example?
I really don’t know the answer to these questions, so I would appreciate your thoughts.
God Bless,
Robert
Interesting, Jimmy. You seem to have done a good bit of research into this. I’m still trying to lose some weight I gained during my first pregnancy, but I hit a floor I can’t break through. Incidentally, I’ve tracked my daily calories for a couple of months, and I fluctuate plus or minus a bit over 500 calories between one day and the next. I’m trying to stay between 1500 and 2000, but have a hard time staying in that range. This is a bit more variation than you were supposing. Hope you have further installments to this weight loss thread, I’m keen to read more.
READER ROUND-UP
Jeff: Thanks, I figured that you were simply being a bit hyperbolic. Congrats on your weight loss!
Robert: See new article in the main blog answering your questions.
Norma: Thanks. I’m sure we’ll be doing more on this topic. Diet is a very controversial subject, and that tends to breed new installments of a discussion.
Incidentally, I don’t mean to imply that people don’t have fluctuations in how many calories they eat per day; it’s just that the average tends to remain about the same over time unless they’re in a period of significant weight gain or loss. There is day-to-day fluctuation. Your target range of 1500-2000 calories is basically 1750 calories per day, plus or minus 250 daily fluctuation.
The main thing exercise will do is increase your muscle mass, and therefore the number of calories you use to do simple things like walking.
I lost 20lbs in about 25-30 weeks (a little slower than I had wanted, but okay, and healthy). I used the hacker’s diet (do a google search), which is a good resource for everyone, especially nerds. I remember when my dad was doing the weight-watchers ‘point’ system, they allowed you to save points for up to a week, so that’s what I do. I allow myself to save up calories over a week maximum to spend on a big dinner, desert, etc.
My wife and I have fallen off the bandwagen a bit recently, but because we were loosing weight, now we’re just stationary. I’m hoping to get back to the routine again soon.
I was always told that muscle adds body weight. Is this true? Thus, would it be advisable for a person whose objective is weight loss to enage in calisthenics or weight lifting?
Muscle is indeed matter, and so adds weight. The point is that
1. the exercise to build muscle burns calories.
2. muscle is more compact than fat, so you can weigh the same and be thinner.
Thank you, Mary!