The debate about low carb diets goes on its merry way, and probably will for some time now. There was a hullaballoo about a diet study – last year, if I remember right – which purported to match low carb up against low fat diets, and it was greeted with delight by everyone who was irritated by the low carb people, because the two diets came out about with about the same results. Hah! No difference!
But when I had a look at what they actually did, it was disappointing. They hadn't done what most low carb folks would call a low carb diet at all: they'd just swapped the proportions of the macronutrients around in a standard calorie-restricted diet, which completely misses the low carbers' point. Their point is not that a calorie of carbohydrate makes you fatter than a calorie of protein. Their point is that a calorie of carbohydrate makes you hungrier than a calorie of protein: so a high carb diet leads to overeating. If you restrict the calories, you prevent that effect from appearing. Of course the low carb diet came out the same as the low fat one.
Studies comparing low carb diets with others show a small but consistent advantage in compliance; but the effect is not as big as I had thought it would be, in the first flush of my low carb enthusiasm. And the insulin resistance story is not looking nearly so clear as an evangelical Atkins-ite would expect. It's all a bit puzzling.
My own low carb experience was extraordinary. I've been overweight nearly all my life, and I've tried and failed at a number of diets. The low-carb experience was radically different. Suddenly – for the first time in my life – I was not hungry all the time. I wasn't thinking about food all the time. I could forget – forget! – to eat lunch. It was a deeply liberating experience. I thought I'd finally found it, and screw the dietitians who pointed to the kidney problems of rabbits force-fed steak. It wasn't that I even particularly wanted to be lean, by that time: what I really wanted was not to be hagridden by such an embarrassing obsession with food. And I'd found it. I was finally in a reasonable relationship with food.
Well, this went on for a couple weeks. I lost a lot of weight, and lost it quickly. I was eating all I wanted. Passing thoughts of cake and potato chips left me unmoved: I didn't even want the stuff any more.
In a couple more weeks, though, things got rocky. I started craving the forbidden carbs: craving even bread, which I'd never craved in my life before. Fruit, which was now off-limits, tantalized me. All that sugar! I managed to stay away from it, with an effort, but I wanted it. With dismay, I saw my old obsessiveness beginning to return. And I really didn't feel all that good. I was getting sick of meat: and I was worried a bit about all the nitrates I was eating.
I soldiered on, until a sale on pepperoni at my grocery store. Pre-sliced pepperoni, like they put on pizza. Cheap! Hardly a perfect food, but it would feel like an indulgence, without kicking off those insulin swings. I examined the labeling closely. (One thing you learn, following a low carb diet, is that all kinds of things are loaded with sugar these days, including, for instance, most commercial beef jerky.) This was fine. No sugar, no carbs at all. I bought a package of them, maybe two. And I went home, settled on the couch, and proceeded to eat almost the entire package. And a day or two later I did it again. There was no way to avoid understanding that I had managed to do what was supposed to be impossible: I had binged on fat and protein. What's more, I wanted to do it again.
It was a discouraging moment. I hadn't found the magic way out, after all. The insulin story just didn't account for what had just happened. Had I just been fooling myself? I couldn't believe that, either. The experience of being free of hunger, free of craving, had been too profound, too liberating.
I floundered for a while, diet-wise. Put most of the weight I had lost back on. But I kept reading and thinking. In particular, I came across Stephan Guyenet's Whole HealthSource blog, which introduced me to some of the research on palatability and satiety. I don't know of a better introduction to this whole topic than just browsing his blog posts labeled “hyperphagia.” (Hyperphagia, for those not Greekly inclined, means “eating too much.”) The neurology of all this is fascinating, but the upshot is that eating foods that are exceptionally tasty disables the ordinary satiety mechanisms that tell us we've had enough. If this is true, then the low carb people probably got the mostly rightly answer by accident. It's not the insulin responses that drive overeating; it's the over-tasty food. The insulin responses are important – they make the overeating particularly unhealthy – but the driver is simply that our food tastes too good. It's laced with sugar, salt, and fat, and we gobble it up: our brother rats do exactly the same. It's difficult to create food that tasty without carbs, but – as my pepperoni experience demonstrates – it can be done. And if it can be done, you can rest assured that the food labs at General Mills etc. will do it. And package it, advertise it, and deliver it to you.
A lot of diet programs have recognized this for a long time, although the neurology of it was not even guessed at until recently. Weight Watchers, I recall from my stint with them long ago, spoke of “red light foods” – foods that you find that you simply can't stop eating. These will actually vary from person to person. They will also vary over time. But they're easy to identify subjectively: I just look for the things that I'll eat even if I'm not hungry, even if I'm full, even if it makes me uncomfortable. I'll eat barbeque potato chips until my stomach bulges and my hard palate is sore. I'll eat enough peanut M&Ms at a sitting to supply the calories of two or three ordinary meals. Those are the foods I have to avoid. I eat them only on special occasions, and in restricted amounts, and I DON'T have them around the house, certainly not where I can see them.
So my diet, put simply, is this: don't eat stuff that tastes too good. This may strike you as bleak and joyless, but the fact is that plain ordinary food actually tastes fine, once you're no longer blasting your taste buds with these manufactured foods. I don't really think the sum total of enjoyment I get out of food has decreased, since I started restricting the over-tasty stuff. A secondary effect of those foods – which are almost all artificial, unhealthy, over-processed things in the first place – is to blast your palate and make it indifferent to the pleasures of real, ordinary food. Once I recovered from that I found that a plain undressed salad, or a simple baked sweet potato, could taste really extraordinarily good.