If simply eating too many calories caused me to gain weight then I should be permanently gaining weight every time I eat a pizza and feel stuffed.

February 22, 2011 3:09 PM

If simply eating too many calories caused me to gain weight then I should be permanently gaining weight every time I eat a pizza and feel stuffed. Yet, I don’t. What factors decide a person’s natural weight? I was watching a documentary about Rocky (the most recent one) and how Sylvester Stallone got in shape for it and did the last part of the movie first while he was still in good shape. It sounded as if his body was going to just lose shape the moment he stopped training. That made me wonder if even people like Stallone have a natural weight that they must fight against every second of every day.

As a general rule I find that I stay the same weight (roughly 197lbs) as long as I only eat when I’m hungry.

A few years ago I dieted and lost about 10lbs over the course of about 5 months. I thought that I was losing weight slowly and that it would therefore be easy to keep off. But, that xmas I stopped weighing myself for a couple weeks and simply ate when I was hungry. I didn’t pig out, I just ate the normal xmas food that my parents usually serve. After getting home I found that I had gained all the weight back in about 2 weeks.

That was when I decided that dieting was a waste of time. Two weeks off of dieting and months of effort was gone down the tubes. In the few years since then I’ve stayed the same weight (about 197lbs) and I find that I never gain any weight when visiting my parents over xmas. If it was simply a matter of calories it seems like I should gain 10 pounds every year at xmas. Yet, I don’t.

Why is that? I suppose it’s possible that I was hungrier and ate a lot more than normal during those two weeks, but I don’t remember it that way. It sure seems like my body has decided on a weight that it likes and just wants to stick to it.

I know that there are things like metabolism slowing down, but that doesn't explain why I end up at a specific weight. How does my body decide that 197lbs is where it wants to be at?

posted by HappyEngineer to science & nature (25 answers total)

"If simply eating too many calories caused me to gain weight then I should be permanently gaining weight every time I eat a pizza and feel stuffed."

Eating too many calories will always cause you to gain weight. Eating until stuffed is a good way to eat too many calories, but the more you eat the more it usually takes to make you feel stuffed, even if you usually stop long before becoming stuffed.
posted by tel3path at 3:14 PM on February 22, 2011

Yes every nutrition expert will tell you that "Diets don't work" (this will advice gets continually ignored too). This is because basically everyone runs into the same realization that you can't just "diet" for a while lose weight and then return to your normal eating habits (even for a few weeks). Real "keep it off" dieting requires a lifestyle change there's no way around it.
posted by bitdamaged at 3:18 PM on February 22, 2011

The study described in this article pretty much confirms your intuition that we have "weight setpoints" that determine our natural weight.
posted by muddgirl at 3:19 PM on February 22, 2011 [4 favorites]

If simply eating too many calories caused me to gain weight then I should be permanently gaining weight every time I eat a pizza and feel stuffed.

The flaw in this thinking is leaving out the "calories out" part of the "in / out" equation. If you eat more calories than you burn, you gain weight.

In your case, it sounds like you have a fine metabolism and a burning-calories routine that keeps you more or less even -- a process that itself is governed by a freaky mix of genetics, hormones, activity levels and many other things that nobody really, really understands.

Anecdote: I used to cover the NFL as a sportswriter. There were two kinds of players -- guys that gained weight and guys that lost weight. The guys that gained weight couldn't do much to stop gaining over time. The guys that lost weight ate everything in sight and still had trouble maintaining large amounts of muscle mass, which they really, really needed to do to stay competitive. Both groups maintained similar levels of activity.

Go figure.
posted by Cool Papa Bell at 3:21 PM on February 22, 2011

If simply eating too many calories caused me to gain weight then I should be permanently gaining weight every time I eat a pizza and feel stuffed. Yet, I don’t.

That's not true at all. Think of calories like gasoline for your car. Your car gains weight every time you put gas in it (at about 8lbs per gallon). *This is not a permanent condition* When you drive, you burn that gasoline and the car gets lighter again. Just because you've stuffed your car full of gasoline doesn't mean it can't get lighter again.

Your body does the exact same thing with the pizza. It doesn't matter how stuffed you feel as soon as you finish it as long as you burn it off eventually. If you continually intake calories faster than you expend them, you will eventually gain weight.

This doesn't really answer your main question, which is, "why does eating the amount of food that causes me to maintain a 197lb weight easiest for me?" but it does address a misconception you seem to have.
posted by tylerkaraszewski at 3:21 PM on February 22, 2011

My understanding is that body weight, like height, is highly controlled by genetic factors. Indeed, various papers estimate that around 70% of the variance in weight between people is due to genetic factors. See here and here, for instance (hopefully neither is behind a paywall). So your weight setpoint is largely determined genetically, though of course if you eat lots of high calories foods you'll weigh more than that, and if you starve yourself, you'll weigh less than that. So in one sense, your body 'decides' to be 197 pounds because that's what the genes you inherited are telling it to do.

Your body regulates this partly by regulating how much you eat, but it can also regulate activity levels so that you burn more calories, and there are also processes that regulate how much energy is stored as fat, and I think even regulate energy absorption from food.

Disclaimer: I am not an expert on any of this, I just heard an interesting talk about it a few weeks ago.
posted by pombe at 3:25 PM on February 22, 2011 [2 favorites]

Real "keep it off" dieting requires a lifestyle change there's no way around it. --- Weight Watchers, for example, tries to teach you to make better eating choices, rather than having you stick to a strict diet. You could eat a cup of broccoli or a cup of ice cream. Both will make you feel full, but one has a bigger impact on you, and one has a lot more calories than the other. Even still, the level of success isn't anywhere near 100%.
posted by crunchland at 3:26 PM on February 22, 2011

In my understanding, all pop wisdom about weight loss and gain, including much of what will be posted in this thread, is wrong. If you really want to understand what's happening, I would start reading through this blog:

http://www.180degreehealth.blogspot.com/

If you're hungry and losing weight, your body thinks it's starving and is priming itself for fat storage. As soon as you give up and start eating to satiety (i.e. eating as much as you want), you'll start gaining weight and usually will overshoot your previous weight. (Overshoot is your body's protection mechanism against further starvation.) If you try again, and start eating less, making yourself hungry, and losing weight, the cycle happens all over again.

If you have been starving yourself and you start eating as much as you want, you'll initially gain weight and may even get hungrier and hungrier. This can last for months. Eventually, as long as you keep eating, you'll start losing weight again. As your body repairs itself from weight loss damage, decides there's plenty of food in the environment, and goes out of starvation mode, you start losing weight.

There are additional subtleties, but the basic idea is you need to trust your body. The only way to lose weight without hurting yourself and gaining it back is to eat when you're hungry and eat until you're not hungry anymore. Also, you need to be eating plenty of fat, carbs, and protein. Do not leave anything out.
posted by zeek321 at 3:33 PM on February 22, 2011 [1 favorite]

What you're talking about is referred to as the body weight set point.

The general idea behind this theory is that after time your body adapts to a weight that it is happy with and tries to maintain that weight.

The best analogy I have heard of is thinking of your weight as a temperature set on a regulated thermostat.
If you go below the set temperature the heat kicks on (eat more, metabolism maybe slows) if you go above that temperature the cooling starts (not hungry, metabolism increases).

There is an idea behind this theory that you can make a new set point by keeping the same weight for a months to 6 months, depending on the person.

I semi-subscribe to the idea that a normal, healthy, functional body will try to keep at roughly the same weight without a swift kick in the pants.
With that said, I believe that genetics is really no match for simply eating a lot and lifting to gain mass, eating a lot and doing nothing to gain fat, or eating nothing to shrivel up and eventually be a rail, etc...

OP, your self example isn't very good anyway. Do you eat enough pizza to be stuffed every single mean, every day, once a week?
Count your calories exactly and I bet that your monthly totals come out to be almost the same every month.
You not gaining any weight at the next Christmas the next time doesn't mean much either. Your maintenance level, even if it's just 10 extra lbs of fat, is higher at 197 than it is at 187.
posted by zephyr_words at 3:44 PM on February 22, 2011 [2 favorites]

Good Calories Bad Calories goes into a lot of detail on this subject. It's a pretty dry, technical book, but still fascinating if you're into that sort of thing. Basically there are a lot of interrelated processes in your body that tend to keep your weight constant as long as you eat in response to hunger.
posted by shponglespore at 3:46 PM on February 22, 2011 [5 favorites]

Eating a lot more than normal on one occasion won't make you fat; you'll just poop a lot more than usual the next day. There needs to be a regular pattern of eating more calories than you use before you'll notice any significant change to your body composition.
posted by Sys Rq at 4:27 PM on February 22, 2011

OP, your question is a prime example of how anecdotes do not equal data. Your experience happened once, and you don't really know all the factors that were at play.

(Lots of answers are falling in to this trap too)

There's lots of good reading recommended in this thread, so try to read up on the topic yourself so you can better relate what's happening to your body with what science knows about how our bodies work.
posted by auto-correct at 4:34 PM on February 22, 2011

If you eat a pizza and get stuffed, and that's more calories than you usually eat in an evening, you will probably eat fewer calories the next day to compensate. I think we do this subconsciously.
posted by bearette at 4:37 PM on February 22, 2011

There seems to be at least one factor that hasn't been mentioned. You say you only eat when you are hungry, and that you stay at 197 lbs so that must be where your body "wants" to be.

My guess is that you have a certain assortment of foods that you normally eat (the odd getting-stuffed-with-pizza notwithstanding), and so you take in roughly the same calories from one week to the next. But if you were to change the things you eat (still only eating when you are hungry), you might find that your body would change to another weight that stays consistent over time if you continue to include that food in your diet (that is, a permanent change instead of a temporary/"dieting" change).

For instance (and I have no idea what you eat), but if you were to eat brown rice and vegetables a few times a week where now you eat spaghetti and meatballs, and do this consistently, you might find that your body "wants" to be 191 instead of 197. Conversely, if you started eating more cake and fewer vegetables than you do now, on a regular basis, then your body might "want" to be 205.

Please don't think I'm making any judgements about what you eat. I don't know what you eat! I'm just saying that "only eating when I'm hungry" is one factor, but what exactly it is you are eating is another factor.
posted by Glinn at 4:57 PM on February 22, 2011

Eating a lot more than normal on one occasion won't make you fat; you'll just poop a lot more than usual the next day. There needs to be a regular pattern of eating more calories than you use before you'll notice any significant change to your body composition.

Exactly. Our body doesn't use everything we eat. Very simply, it goes like this. Our intestines absorb what they can. That turns into blood sugar, which our body uses as fuel. Any fat cells that are empty grab up some of that sugar to refill themselves. Meanwhile, various processes try and keep the blood sugar regulated. What doesn't get used, gets pooped out.

The more fat cells you have, the more calories they can store. The emptier they are, the more of [some hormone] they secrete to make you hungry.

Full fat cells reproduce at a rate greater than their replacement rate. Empty ones don't. Depending on who you believe, the number of fat cells never drops, or it takes a really long time for them to drop.

So a person with more fat cells is going to use up and store excess calories more efficiently than someone with fewer.

(And then you have endocrine differences and diet differences- high fiber food "transits" more quickly and has less opportunity to get absorbed. That's why prunes make your butt explode. Calories that the body has to work harder to absorb are going to be less "fattening" than easy ones like carbohydrates. Cardio exercise burns calories while you are doing it. Muscle building exercises burn calories while you are doing it AND for days later as the muscles repair themselves. Thyroid differences change things, stress/cortisone differences, exercise differences...)

Timing of eating makes a difference too. Two identical people without any obvious disorders can eat the EXACT same food and change only the timing and have widely different results. Someone who regularly eats before bed is going to develop more fat cells to store up all that food for the next day. They are also going to be miserable, because those emptying fat cells are going to be hormonally screaming "feed me!!!".
posted by gjc at 5:01 PM on February 22, 2011 [6 favorites]

Seconding Good Calories, Bad Calories as a great explanation of why, as you point out, the "calories in vs. calories out" theory doesn't always work. The author, Gary Taubes, posted a blog on just this topic that you might find interesting: The Inanity of Overeating. Tom Naughton, the creator of the nutrition documentary "Fat Head," also discusses this in his blog here and here.

Here's my quick attempt at summarizing what they explain in much greater detail: Whether you gain weight or not has far less to do with "over-eating" or "under-exercising" than we commonly think. What is much more important is whether your metabolism is well-regulated (as yours appears to be) or not (as is the case for many, many people). However, because "calories in vs. calories out" seems to make so much sense and seems to work for some people, it's much easier to blame people who gain excessive weight for simply lacking willpower and therefore eating too much or exercising too little than it is to look into the actual reasons behind why their bodies have developed a dysfunctional metabolism. The book goes on to explain why and how our metabolisms get so out of whack (it's primarily hormone-related, specifically the insulin hormone) but the jist of it is that losing/ gaining/ maintaining weight is not nearly as simple as just calories in vs. calories out.
posted by platinum at 5:38 PM on February 22, 2011 [1 favorite]

Gary Taubes's Good Calories, Bad Calories, which has been mentioned before, gets good reviews even from some of his critics (e.g. G. A. Bray, Obesity Reviews 9 (2008): 251-63, doi:10.1111/j.1467-789X.2008.00476.x).

N.B. Bray, in the review mentioned, notes that human bodies are remarkably good at regulating calories. Over the course of a year, an average American male will eat around a million calories. (Women will eat somewhat less). A gain of 1 pound per year, typical for people over 30, equals about 3,500 excess calories. Therefore, a typical person takes in only 0.35% more calories than they burn over the course of a year. Bray's conclusion is that we have pretty impressive internal systems for regulating our caloric intake.
posted by brianogilvie at 5:51 PM on February 22, 2011 [1 favorite]

Homeostasis is the term for the way the body's systems attempt to self-regulate. Hunger and metabolism are affected by various hormones which, in normal functioning, attempt to maintain the body's status quo. This is what "set point theory" refers to. Leptin is one of the important hormones in terms of regulating appetite. You can read about leptin and its role in fat loss here and here.

While it's well-established that the body has systems which work to maintain homeostasis, this of course doesn't mean it's not possible to disrupt it and change levels of muscle and fat. But it takes concerted effort and consistency.

Also, while Good Calories, Bad Calories has some good information in it, Gary Taubes is not a scientist and the book is not the last word on nutrition. Current research seems to indicate that low-carb eating, like Taubes advocates, can help satiety and aid diet compliance, but offers no advantage independent of caloric reduction. You can read more detail here.

I was watching a documentary about Rocky (the most recent one) and how Sylvester Stallone got in shape for it and did the last part of the movie first while he was still in good shape. It sounded as if his body was going to just lose shape the moment he stopped training.

More like the moment he stopped taking steroids.

Also, you need to be eating plenty of fat, carbs, and protein. Do not leave anything out.

Protein and fat are essential nutrients, carbs are not.
posted by Anatoly Pisarenko at 6:09 PM on February 22, 2011

Protein and fat are essential nutrients, carbs are not.

Some people get hurt by leaving out carbs. I did.
posted by zeek321 at 6:13 PM on February 22, 2011

Some people get hurt by leaving out carbs. I did.

Ok, well I have no idea what that means, but you're free to check out the citations provided here:

"Carbohydrates are a common source of energy in living organisms, however, no carbohydrate is an essential nutrient in humans. Carbohydrates are not necessary building blocks of other molecules, and the body can obtain all its energy from protein and fats."
posted by Anatoly Pisarenko at 6:23 PM on February 22, 2011

Anatoly Pisarenko: "Protein and fat are essential nutrients, carbs are not."

It's possible to do without carbs, but only with a lifetime of preparation.

The Inuit have (relative to us) a really low-carb diet, mostly because the tundra doesn't support much in the way of grains, tubers, etc. They get almost all of their calories from meat, including vitamin-rich organ meats. So, in a sense, yes, it's possible to do without carbs.

On the other hand, if you biopsy an Inuit man, you'll see that his liver is absolutely enormous and has similarly extreme biochemical changes (enzyme expression levels, etc.) to handle all the meat. After the first studies were published of the Inuit diet, a lot of people trying to mimic it became extremely ill because they hadn't had a lifetime to work up to it.
posted by d. z. wang at 6:31 PM on February 22, 2011 [3 favorites]

Stephan Guyenet, a researcher in the neurobiology of obesity, has posted some interesting articles on the topic.
posted by Earl the Polliwog at 7:13 PM on February 22, 2011

What Anatoly said. You're fighting homeostasis. It's possible to reset your body's weight at a lower point, but it takes a while (I think at least couple years of maintenance is the rule of thumb). Your natural hunger levels will adjust quicker than that, but certainly not within the period of a few months.

Other possibilities are when you ate Christmas food, it contained a good deal more sugar and carbohydrates than your healthy eating plan and this inflated your muscle glycogen and encouraged your body to put on water weight. If this is the case, then if you returned to your healthy eating patterns after Christmas it's quite likely you'd have seen most of that weight drop off, if not immediately then certainly within a matter of weeks.

It's possible to do without carbs, but only with a lifetime of preparation.

Can you give a citation for the "no carbs = death" conclusion? I don't know where you are getting your information about nutrition, but I suggest you stop listening to that source. I know countless number of people who cut out carbs and function healthfully and happily, certainly better than they did when gluten and grains were in their diet. When I limit my carbs, I find my athletic performance and energy levels go through the roof. I'm not Inuit.
posted by schroedinger at 8:39 PM on February 22, 2011

I don't have an answer to your question, but I want to say that I also have a set weight that my body decided it likes and that it always comes back to on its own. In the past I've lost weight from dieting and came back to my normal weight when I stopped watching what I eat, lost weight from exercising a ton and came back to my normal weight when I stopped going to the gym for hours a day, lost weight from being super depressed and came back to my normal weight when I started feeling good again, and gained weight several times from, well, eating too much, and came back to the same weight after I stopped pigging out. So if I just live without thinking about my weight and without over-eating or dieting, and with moderate exercise several times a week, I always always come back to the same weight. This weight is a little more than I'd like to be, and it's slightly on the overweight side, but for me it's not worth the effort to constantly be dieting to keep the weight down, because I am healthy and strong and that's all that matters to me. I do sometimes think about how I hear that even losing 5-10 pounds can make it so much easier for your heart, and at that point I sometimes try to diet and exercise more, but no matter how much effort I put in, my body still comes back to my normal weight.
posted by never.was.and.never.will.be. at 1:29 AM on February 23, 2011

I know this is a massive derail: but most people who go "low carb" aren't actually going entirely without carbohydrates. They may cut out pasta, and rice, and bread, but they still eat veggies and fruit, nuts, diary etc, all of which contain carbohydrates (aka sugars). Almonds, for instance, contain around 20% sugars.

In short, simply cutting out simple starches does not entirely remove carbs from your diet.

Yes I know there are people who go low carb and cut out everything except meat and fat, but I've yet to meet any of these people and I hang out in weight-lifting, paleo-eating circles.

/end derail.
posted by jasperella at 4:50 AM on February 23, 2011