Tuesday, February 07, 2012

Carbs, fats and biology, or "You're doing great just as you are!"

Weight gain and loss holds my attention more the older I get. The fantasy still lives, but I have to admit that being thin is no longer enough to make me look young. At the age of 45, I could weigh 115 pounds and still not look young-adult-slim because I'm no longer a young adult. These days, too little weight would actually make me look older than too much weight.

So it's just as well that getting skinny seems increasingly out of my reach. Here's the information that has recently impressed me:

1. Eating carbs triggers weight gain in a way that eating fat (and protein) does not.
2. Our bodies never stop trying to maintain the highest weight we've ever reached.

The first one is sobering, but I can live with it. The article I read about carbs vs. fats is called "Pasta, Not Bacon, Makes You Fat. But How?" It includes some nice graphics that show the steps by which carb-heavy foods trigger insulin production which slows fat burning and increases fat retention. And that chemistry, of course, leads to weight gain. As much as some might want to believe that weight is just about calories-in/calories-out it's not.

Weight is not just about calories-in/calories-out.

That is to say, that it's not enough to create a deficit in your daily calorie intake by exercising more and eating less. The kinds of calories you eat also matter because your body treats different kinds of calories differently. Calories that come from carbs like bread, pasta, rice, grains, potatoes, alcohol, sweets and sweetened drinks trigger your cells to hold on to fat. Calories that come from protein and fats don't do that. You eat an avocado and your cells continue burning fat at their regular rate. You eat a bowl of pasta with Italian bread and it all slows down. Check out the article. It might make you look at that sandwich differently.

The second item that caught my eye is even more sobering, and yet kind of a relief. "Losing Weight: A Battle Against Fat and Biology" explains that once you gain weight, your body sort of memorizes that weight and never stops fighting to stay, or get back to, that size.

Let's say I'm a 5'2" woman (157 cm tall) who eats about 2000 calories a day, exercises two or three times a week and stays around 125 lbs/57 kg (I'm just making up wild stories here). Let's say that during an emotionally difficult period, I hit 145 pounds. According to this research, my body chemistry locks in on that 145 pounds and wants to stay there. When I try to lose, my body begins producing more hormones to make me feel hungry. As my body senses that it's getting smaller, it slows down my metabolism, so I lose weight more slowly. Basically, my body fights me however it can to maintain those 145 pounds.

Now let's say that through raw determination I change my diet, cut out all the junk food and start exercising every single day for an hour. Gradually, (oh my god, so gradually), I get my weight back down to 125. Success! But you know what? I can't go back to my former 2000 calorie-a-day, 3-workouts-a-week way of life. Between exercise and eating, I must maintain a net of maybe 1800 calories a day to stay 125, and that's a permanent change. I can never go back to the way I used to live and still be 125 pounds.

Why, O Lord, why?

Because gaining weight changes your body chemistry.

Once you've been big, your body never stops wanting to be big.

Your body is genetically programmed to hold onto every scrap of energy it can. Any weightloss, even after extreme obesity, is seen on the cellular level as a crisis state. And those cells will never be convinced otherwise. They keep producing hormones to increase your appetite and lower your metabolism until you get all that weight back. Only then are they happy.

People who have lost large amounts of weight essentially live in a state of long-term starvation as far as their cells are concerned. Those cells never stop wanting to go back to the biggest size they were. This is why, once it starts, the battle against being overweight rarely ends.

But sometimes it does, and painlessly. My husband used to be a few dozen pounds overweight and was the chubby guy in many photos from about 15 years ago (yes, he approved me posting this). Several years ago he lost about 40 pounds by changing the way he eats and he's never had a problem maintaining it. He's simply never gone back to eating in the old way (all night long), but it doesn't feel like a sacrifice to him. So there are good weightloss stories, too.

Here's my good weightloss story: this news about biology working against me actually relieves me because it means I'm not a failure. My inability to get back to and maintain my ideal low weight doesn't mean I have no willpower or discipline. It doesn't mean I'm lazy and unable to stick to a plan. Lack of thinness is not a moral failing. I'm fighting a wretched evil battle with my own biology, a battle that is wicked hard to win. Let us all feel proud of every ounce we ever have managed to lose.

In fact, I congratulate myself for every pound I've managed to not put on. For years I've heard that it's easier to prevent weight gain than to lose weight later, but I never really knew what it meant. Now I know it refers to how difficult it is to permanently lose a significant amount of weight, and how, compared to that, avoiding weight gain altogether is much easier.

So let us all congratulate ourselves that we are not even chubbier than we are at this very moment. Better yet, think of your highest weight ever. Now add 50 pounds (or kilograms) to it. Now rejoice that you've never hit that weight. Isn't that great? You never have to worry about keeping that extra 50 off because you've never hit it to begin with. Well done!

I'm serious. From now on I'm taking it easy on myself about weight. I will focus on eating in a healthy way (low carb) and exercising for fitness, but no more tormenting myself with, "Well? When am I going to really take control and get back to my college weight?" From now on I'll say, "I look great. If I can just stay as I am, that's success right there!"


Mick said...

Never heard this before but the fact our body wants to return to its biggest size ever makes a lot of sense. Its quite apparent a lot of us regular dieters pile the pounds back on the minute we stop dieting.

good post and i agree the ultimate aim should be about fitness.

cindylu said...

This kind of stuff is so interesting. I was overweight from childhood to my late 20s. Then I lost the weight through Weight Watchers, basically counting calories and working out 4-5 times a week. I've kept off 50 of the 60 lbs I lost for two years without much trouble. I don't count calories or WW points anymore, but I also workout about 5 times a week.

The NYT magazine had an article on this too in December, The Fat Trap. It bummed me out to realize that I probably burn fewer calories doing the same activity as another woman of similar height/weight who was never overweight or obese.

Anyway, I hope more research is done to really help us understand why maintaining weight loss for a long period of time is so difficult.

Regina Rodríguez-Martin said...

Cindylu - I think this is just more evidence that the human body is made to conserve calories and there's no way around it. We can't reprogram our bodies to burn calories faster, but we can program them to burn them more slowly (sadly). We Americans are food addicts and desperately want science to find a way to let us keep eating like Americans, but stay healthy. We're on denial that it's our diets and habits that must change, not the chemistry of our bodies.