Why do we eat stuff that's bad for us when our stated aim is to lose weight or "get in shape?"

In a 2010 study entitled Food reinforcement, delay discounting and obesity, Dr. Leonard Epstein and colleagues review the work that’s been done so far in the behavioral economics of obesity. This branch of science tries to distinguish how human beings make complex choices. Humans must balance their experience of the world with limited resources in terms of time, money, and availability of activities or commodities. A main question of research interest is: What goes into the apparently harmful decisions that we make with regularity? How can an intelligent person consciously make choices which are ultimately not in their best interest?

Researchers have so far laid out a working vocabulary for starting to analyze food ingestion and exercise decisions. Important pieces of that vocabulary include:

Reinforcement: Things are reinforcing if they provide pleasure in themselves. Food is self-reinforcing. More palatable food is, almost by definition, more reinforcing.

Delay of gratification: Being willing to have less of something now, for more of it later. Typical studies are to offer a child one marshmallow now vs. two in five minutes. For adults, the analogy is $10 now vs. $100 in a month.

Discounting: The process of working out whether two marshmallows is “worth” the trouble of waiting. What’s two marshmallows in the future worth in right-now, marshmallow terms? How our brains process these intuitive discounting equations affects our decisions. Poor ability to visualize what something is “worth” in the long term can lead to bad decisions in the present.

Alternatives: sometimes we aren’t given a choice of different quantities of a desired thing, but two different things.

What we find when we try to look at things in these terms is that obesity is an intractable problem for very good reasons. Most poor food choices are very reinforcing and the alternative healthy foods can be literally difficult to swallow.

Gummy Bears vs. cauliflower?
There’s not much to wonder about there.

Unlike financial decisions, such as foregoing purchasing a television today, in order to save money for a better television in a few months, the delay of gratification needed for food decisions doesn’t have a very clear, definable payoff. We don’t forego a marshmallow today in order to receive several bags of marshmallows in a few months. We forego the marshmallow in order to have something called “better health,” perhaps not in a few months, but in a distant future. What sort of a payoff is “better health”? As far as trying to figure out whether it's "worth it," how many marshmallows do I have to forgo to get the "better health"? Not just one, but many, perhaps all of the available marshmallows for the remainder of my existence. All of those, and then most other very reinforcing foods, forever, as well.

Hmm...let me try to calculate whether I like this deal...
For many people, the benefits of better health are not worth the calculated sacrifice and restraint. Therein lies the problem. We want to be skinnier, but we don’t want the life that results in sustained weight loss. Who would? I’m in a position to tell my patients that I can make them skinny if they are willing to: write down everything they eat, systematically reduce calories daily, avoid fast food, avoid most junk food snacks and desserts, avoid simple carbohydrates, learn to live with occasional hunger, walk an hour every day, wear a pedometer and track activity, stop eating a very rich diet and eat a much simpler one, learn to lift weights and make being healthy through diet and exercise, rather than medications, their number one priority and interest . . . I'm exhausted just from writing that!

Explain to me, who, in their right mind, would say yes to that proposition? The answer is: almost no one, which is why weight loss studies invariably show very few individuals losing and keeping off a substantial amount of weight. I believe my patients are generally aware of what weight loss would require and they have already said “No.” They’ve been saying “No" to that idea for a very long time now. That’s why they weigh what they weigh.

I believe the best estimation of how important being a healthy weight is to an individual is to put the individual on the scale. We all weigh exactly what we should, given our fairly hardwired, reinforced preference for palatable food and our quite reasonable discounting of future “good health.” It’s not that people don’t want to lose weight. It’s that they want to lose weight less than they want to continue living a life that’s largely similar to what they are living.

Our body shape communicates how important these things are to us. Our current body is the sum total of every decision we’ve made on the subject. All the meals we’ve eaten (or avoided), all the activity we’ve done (or skipped), sports we’ve played (or watched), gyms we’ve joined (or quit), every diet idea we’ve embraced (or given up) --all that is right there in front of us. On average, this is how much it matters to us. This produced the current body that I'm discussing with the patient on that first clinic visit. “But,” people will say, “that’s really not fair, I’ve dieted and lost weight over and over, I’ve gotten into shape, then the weight comes back…”  I know.  I absolutely know that. Of course you have done things to lose weight, that’s why you’re not heavier than you are. All that stuff you’ve done is part of what got you here: Your current body. The diets and the good stuff are all included too. This is the sum of all that. If you hadn’t done all the good stuff, things would be much worse.

The same is true for me. I happen to be in good shape right now, a few months ago I was a little squishy and several pounds up. I’m not perfect, either. If I did more, I could be leaner and stronger than I am. A real gym rat would look at me and wonder how I can look in the mirror at these scrawny arms and not decide to do something about it. I’ve been leaner and stronger than this in the past. I’ve been in marathon shape twice in the last ten years. I’m not now. I hit the weights harder and had a stronger build just a couple of years ago. Why am I not leaner or in a state of better endurance than I am now? Because, on average, right now, all things considered, this is what my overall health is worth to me. To be exactly this amount of "in shape." I have to make decisions on what to eat, how much time for exercise versus the other things that I enjoy and this has led me to exactly where I am. If I wanted magazine cover abs more than I wanted to avoid the work to achieve those abs, I would have them. I prefer almost every activity available to modern man more than I enjoy sit-ups. Therefore, my abs are my abs. They are exactly the abs I’ve made. And so are yours. We are making all of the day-to-day decisions about our long-term health in a barely conscious part of our brain --but it is conscious. People are not fitter because it’s not worth it to them.

Consider the analogy of financial health, which is even simpler to show how our balance can be different from what our stated priorities are. I have friends who are financial counselors. They could probably help me tremendously if I’d let them. But my financial health is not something that I spend much effort on, and it shows. It would be hard for me to tell a financial counselor that I want to get my affairs organized, because my financial documents show quite obviously that I really don’t. But for argument’s sake, let’s say I got up the courage to call up my financial counselor buddy and make an appointment. He would look at my statements, my income, my taxes, my debts, my savings. He would know the truth about how I’ve been living and the thinking that lies underneath. The exact dollar amount in the bank is exactly how much priority I have put on saving. No more, no less. There’s no judgment in that and no mystery as to how it’s calculated. The number is just the number. After laughing, or crying, or just expressing his concern and sympathy, he would then lay out either a hard or an easy program for me to follow that would get me on track. It would involve: writing everything down, keeping track of expenses, reducing unnecessary trips and purchases, putting aside a certain amount to savings every month…..and twenty other things I obviously don’t want to do. If I did, I would do them! It’s not like I’m totally confused about how I got here.

So does that make me stupid? Immoral? Lazy? I don’t think so. It simply shows my priorities. I’m not at all stupid, lazy, or immoral when it comes to other parts of my life. The financial part is just not my priority. I want to be financially fit, just not as much as I want to spend money on whatever I wish, never track anything and not worry about it. My mental energy is spent on other things. Now, do I sometimes write stuff down, go on a reduced spending regimen, get into better financial shape? Sure, that’s why I’m not even worse off than I am. Does this sound familiar?

Why would I not want to become more wealthy? Well, I do. I just don’t want to live the life that produces more wealth than I’ve got.  It’s not worth it, for me, right now, given what else I’ve got going on. I want to improve, just not enough to actually change anything about my life. Let’s face it: we can complain about our financial or physical health, but we are basically happy with our life, or at least as happy as we can be, things being what they are.

Within reason, most of us are as wealthy and as healthy as we, on balance, want to be. Of course, we all have a starting point. If you are born into a wealthy family, you are more likely to be able to keep that wealth, or make decisions that create more. Same goes for health: Our genetics, our family, the attitude of our parents toward health set us off on the right path or the not-so-right path. Some people have a lucky metabolism that allows them to eat what they want and not gain weight. Not many people though. Probably about the same number of people fit this description as those who are lucky enough to be born into wealth. Most of us have nothing but a lot of effort in front of us if we want to get healthier.

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Epstein, LH et. al. Food reinforcement, delay discounting and obesity. Physiology and Behavior 2010, 100(5) 438-45.