The Daily Apple: Apple #718: Why Am I Hungry if I'm Fat?

Dear Apple Lady,

My body has rather obvious stores of fat available to it. How come when I'm hungry, it doesn't just burn that extra fat? How come my body wants me to eat more food, when it's already got a lot of food stored up in the fat?

Asking for a friend,
A.L.

Well, A.L., I had to read up on this one because I've had that very same question for a long time (imagine that). Based on what I've read, the answer is: fat don't work like that.

Fat cells very nearly have a mind of their own. They don't work the way other cells do and they don't take direction from many other parts of the body. They will keep getting bigger in spite of other processes going around them which should otherwise direct them not to.
(Diagram from QMP's Plastic Surgery Pulse News)

Fat cells in your body are like rich people. You know how when people start to amass wealth, you would think they'd have that much more they'd be willing to share? (This was the theory behind Reagan's idea of trickle-down economics.) But in fact what happens is people raise their bar for what they consider to be the minimum amount of money they need to live on. The more they have, the more they feel they need to protect.

Fat is like that. The more fat you have, the more your body is going to give you the prompt to eat more. As one recent New York Times article put it, "We get hungrier because we're getting fatter."

For quite a while now, the prevailing wisdom about obesity has been that if you're overweight, you've simply eaten too much. Too many calories in, not enough burned. That simple. So all you have to do is un-do that equation. Eat less and exercise more.

Problem is, this is a big fat lie.

This, on the other hand, is not just a joke, it's the truth.
(someecard sourced from All-species fitness)

I watched a really fascinating lecture by this guy, Gary Taubes, writer for Science magazine, who has done a lot of research into the history of science and medical literature on obesity. One of the scenarios he gave is this:

Suppose you've been invited to a really phenomenal dinner. Your friends are going to prepare the best foods you've ever tasted in your life. It is going to be one great big spread of super-deliciousness. They tell you to "Come hungry." What do you do?

My answer was that I wouldn't eat much during the day prior to the dinner. Someone in the audience said, "Exercise." You know, "work up an appetite."

Right, Gary said. To make sure you're good and hungry and ready to eat a lot, you eat less and exercise more.

So why are we telling obese people that the way to lose weight is to do the very thing we know will trigger us to eat a lot?

He does a lot more debunking of the conventional obesity theories and advice. So let me pause a moment here and say, it's time we quit blaming people for being overweight and obese, and started figuring out what we don't understand about how our bodies use food and get to fixing it.

Taubes debunks our current thinking about obesity in order to figure out the real answer behind how obesity works. If we know what's causing it, then we can know how to treat it or stop it.

The deal is that fat doesn't work the way we think it does. We've been told that our body stores extra food as fat and then when it doesn't have enough food available, it will burn off the fat. But it's more complicated than that.

Fat cells want to keep their fat. Fat cells have a membrane that lets stuff in and keeps things from going out. What is allowed in are fatty acids. Some fatty acids that you may have heard of are

Omega-3
Omega-6
Prostaglandins
Palmitic acid
Stearic acid

There are all kinds of them. These are what you get when you eat foods that contain fats. Meat or fish or nuts, for example.

The membrane around the fat cell lets the fatty acids in. Then the fat cell combines these with a type of sugar called glycerol to make triglycerides. This is the form in which fats and sugars are stored in your body. More triglycerides in the fat cell, the fat cell gets bigger, and you get fatter.

Once the fats & sugars are stored in the form of triglycerides, your fat cell does not want to let that triglyceride out. The holes in the membrane are too small for the triglycerides to pass through, for one thing, so the triglycerides can't get out on their own.

A representation of a triglyceride. Three fatty acids plus glycerol. This makes for a big, complex molecule -- too big to get back out through the fat cell membrane.
(Image from Antranik.org)

Another depiction of a triglyceride being made from 3 fatty acids and glycerol, and then being stored in the fat cell of a prairie dog, I think that is.
(Diagram from The KetoDynamic Antidote)

In order for the fat and sugar locked in your fat cells to get out, the triglycerides have to be broken down again into their fatty acid and sugar components, and then those can pass back out through the membrane.

But your fat cells do not want the triglycerides to be broken up. Your fat cells are like, "I worked hard to get these triglycerides. You are not getting these out of me just because you skipped lunch today. Uh-uh. No, sir."

When you get hungry, your body doesn't really see the fat stored in your body as available food. Because the stuff it needs is all locked up in those triglycerides. Think of it this way: When you get really hungry, are you going to take the time to dress and roast and baste a turkey? Or are you going to reach into the cupboard and grab the already-made container of pudding and scarf that down in 30 seconds? You are going for the 30-second pudding.

Literally everything in you says EatthepuddingEatthepuddingEatthepudding.
(Photo and recipe from Fine Cooking)

Your body is the same way.

Your body is like, I'm not going through all the hassle of breaking down those triglycerides. I'm not opening up the fat cell cupboard and mixing up spices and butter and roasting and basting and who knows what else for who knows how long. I need something in my blood, and it's got to be easy for me to get energy out of it because I'm hungry right now!

What's the easiest and fastest thing for your body to break down? Sugars. Highly processed carbohydrates. The ready-made pudding.

As long as your body can get its bloody little fingers on some simple sugars, it is not even touching what's in those fat cells.

So that is why you still get hungry when you're fat.

In fact, it's even likely that when you have a lot fat stored up, your body will tell you to eat more often because of it. Because your body has gotten very good at storing sugar, there's even less of it in your bloodstream, so you'll get the hunger prompt more often.

How are you supposed to get out of this vicious cycle? How are you supposed to burn fat when all fat wants to do is store up more of itself?

It seems like the answer ought to be involved in breaking up those triglycerides, which will make the fatty acids and the sugars available again and deplete those fat stores. But how do you break up those big triglycerides?

The answer is in a hormone.

Various hormones regulate the calorie-burning, food-intaking, fat-storing process. Think about how a child eats a lot and grows bigger. Or how when you hit puberty, if you were a girl, your body started storing fat in places it hadn't before -- breasts and hips -- and that was a good thing. Or if you were a boy, you ate a lot and got taller and also developed muscles. So something is telling your calorie/fat/food-using processes to use food in a certain way when your body was growing versus how it handles food and fat once your body has reached adulthood.

The main thing directing the food/fat traffic is hormones. Different hormones turn on certain processes and turn off others. We typically think of hormones as estrogen and testosterone, and it's true, those are two pretty important ones. But another hormone that is very important in the food/fat process is insulin.

Insulin is not the only hormone working inside the fat cells, but it is the big policeman on the block, so to speak.

Insulin is the traffic cop directing fatty acids and sugars out of the blood into the fat cell. Insulin is the policeman who is locking the fatty acids to the glycerol and putting them in the triglyceride jail. And when the triglycerides want to bust out of jail, insulin is the guard who tries to keep them from busting out.

This is a very complex diagram that includes things not discussed in this entry, but the main point is to notice all the green boxes which contain the word Insulin and the one red box containing the word Insulin. This shows in how many fat-storing processes insulin is involved.
(Diagram by Keith Frayn, sourced from The Eating Academy)

Insulin. The police officer that does not let the triglycerides out of fat jail.

If you can control the insulin, you can control the fat. More insulin equals more fats and sugars in the triglyceride jail. Less insulin means the triglycerides can bust out and be free.

But you do still need insulin, right? Don't people with diabetes have to inject insulin to regulate their blood sugar?

Yes. People with Type 1 diabetes don't have insulin being made in their bodies so they have to supply it. People with Type 2 diabetes have had so much insulin pulsing through their blood, their cells are desensitized to it and don't know it's there and so can't control the sugar in the blood.

So, yes, we do need insulin, but as with most things, we don't want too much of it or too little of it. What's the thing that results in too much insulin? Sugars. Carbohydrates.

Here's the process broken down:

You get hungry
You eat & start digesting food
Sugar shows up in the blood
Pancreas makes insulin to deal with the sugar
Some sugar gets burned as energy right away
Insulin ferries leftover sugar & fat to the fat cells
Insulin makes sure the sugar & fat (now triglycerides) are not getting out
Sugar levels in blood drop
You get hungry
It all starts over again

Of course it's more complex than that, but that's what we need to know for our purposes at the moment.

If we could have less insulin locking up the sugar & fat, it would stay in our blood longer and we'd have it available to burn. We don't want that stuff lingering in our blood too long because that's how you get heart attacks and nasty things like that.

So maybe we do something else to change the mechanism at the beginning of the process. Maybe we make the body work a little harder to get the nutrients it needs. Instead of letting it scarf down the container of ready-made pudding, maybe we make it reach for a turkey sandwich.

Now this is the kind of turkey sandwich I can get into. Not the slimy, weensy, sliced turkey from a plastic package, but hunks that have been cut off the roasted bird, with a healthy amount of mayonnaise and butter and some cheese too, on whole-grain bread. This one is made with roasted red peppers and pesto and fontina cheese.
(Photo and recipe from inspired2cook)

I'm being too metaphorical here. Let me get to the point. The best way to disable this fat-accumulating process is to eat fewer sugars and simple carbohydrates.

When you put more easy-access sugar into your blood, you speed up the whole insulin-making, fat-jailing process. Once the fat is in the jail, your body has practically forgotten it's there, so it asks for more food. If you give it a lot of sugar -- way more than it can burn right away, which is true of those all those sugary processed things like candy bars and soda pop and doughnuts and pudding and children's cereal and most of the things in the mid-section of the grocery store -- if you give it more free sugar than your body can use, it's only going to lock more of it up in the fat jail. It's not going to bust out that stored-up fat, and it is certainly not going to do that if you keep giving it more free sugar.

The only way to break the fat-storing cycle is to quit giving your body more free sugar. You have to make it work for its food. Only then will the insulin police let the triglycerides break up and get out of jail. Only then will you start burning the stored-up fat. Only then will you start losing weight.

So the short answer is: want to lose weight? Eat less sugar.

A good way to help yourself eat less sugar is to follow this map of a grocery store layout. Stick to the outer regions. Avoid the pre-made stuff in boxes in the center aisles. Except for the nuts. I'll go into the center aisles for the nuts.
(Diagram from Medicine in Plain Words)

P.S. When I couldn't eat sugar for a while -- and I mean I had no sugar at all. Not just the typical things you'd think of like ice cream or cookies, but also no bread. No ketchup. No tomatoes. It was intense. I ate almost exclusively protein and vegetables. -- I held to the restriction for about 3 months. And I lost 28 pounds. I wasn't even that much overweight to begin with.

When the problem that precipitated this drastic diet went away, I started eating some sugar again. I gained back the weight I'd lost and then some. :( But I am proof that if you want to lose weight, don't eat the sugar.

P.P.S. I also learned, though another source, that if you're trying to change your behavior, it's much harder to achieve a Don't than it is to achieve a Do. So I'll say that while you're not eating sugar, Do eat proteins. Do eat vegetables. Do eat crunchy, complex things. Do add spice.