I’m doing everything right and it’s not working! If you have ever thought the aforementioned – usually cried in paroxysms of grief after an unfortunate run-in with the Scale of Self Destruction — then you have inevitably wondered Maybe I have a slow metabolism. (Right after you have wondered if your Body Bugg got hit by lightning without your knowledge and/or if your personal trainer secretly hates people.)

One of the most hotly debated theories in the study of human metabolism is whether or not people have a baseline or set point, as measured by weight, that is programmed for each individual body and to which the body strives to maintain. Proponents say this is evidence as to why people have such a miserable time sustaining weight loss over time but opponents say if the baseline theory were true then nobody would ever maintain long-term weight loss and some do. On one hand, lending credence to the set point theory, people tend to weigh similarly to those they are genetically related to (even if they weren’t raised by them, as seen in identical-twins-traumatized-by-separation-at-birth studies). On the other hand, NY Times science writer Gina Kolata’s whole book Rethinking Thin is based on science saying the opposite. Plus they have Jared the Subway Guy and, well, you can’t argue with sandwiches.

The science in this area is still emerging but several studies shed additional light on this. Here’s the Spark Notes version:

1. Calorie deficits work. You cut enough calories and you will lose weight. The devil, however, as he is wont to be, is in the details. As anyone who has ever tried to create a calorie deficit can tell you, it isn’t as easy as calories in, calories out. New research shows that the percentage of deficit taken, the starting point of both body weight and body fat, and the macronutrient ratios in the diet all influence the rate and the way in which weight comes off when you cut calories.
2. The key to maintaining a weight loss is “balancing your energy.” Researchers have shown that people who have lost a lot of weight often overestimate the number of calories they need to maintain their new lower weight and therefore overeat, regaining their weight. When asked, the people reported that they were eating only enough to maintain but when examined by researchers they were eating more than reported. (Not that I blame them, that’s just human nature!)
3. People who have lost weight have similar resting metabolic rates as their weight-maintaining peers. Your RMR is how many calories your body burns while just surviving and seems to adjust in relation to your weight. This refutes the oft-repeated statement – and the set point theory – that overweight people have slower metabolisms, even after weight loss.
4. No two metabolisms are the same. It’s this last point that is the real kicker. While each person’s metabolism may react to different environments (starvation, overfeeding) in a proscribed manner, factors like hormones, body fat percentage, diet composition and, yes, gender, can greatly influence it. If you’ve ever had a roommate who can eat 6 packages of peanut butter cups a day and still stay a size zero (like I did – egads, you should have tried living with her!) while you eat salmon and broccoli every night and can barely maintain a “normal” BMI, then you will know what I’m talking about.

Our metabolisms may not have set points but they sure have enough outside factors working on them to befuddle even the most determined dieter. I remember the first time this truism bit me in the butt. When I first embarked on my health-nut journey (that started out all about the health and ended up all about the nutty) my extra weight came off fairly easily. Yes I had to watch what I ate and exercise but it worked. I lost weight steadily. And then I hit a plateau. All my diet evangelism flew right out the window when confronted with the “But I’m doing everything right by golly!!” paradox.

Other than struggling over the next couple of years to lose a measly few pounds, I didn’t get much insight into this until The Great Over-Training Debacle of 2008. During this time, I had my metabolism thoroughly tested – both in the doctor’s office (they ran tests on my thyroid and my hormones and even my baby maker – which thankfully was unoccupied at that time) and in the gym via hydrostatic weighing and the Darth Vader-on-a-treadmill metabolic testing. Their conclusion? I need 1230 calories a day to go about my daily life. I still remember the professor’s face when he gave me the news, his look daring me to complain. Which I did. Vociferously! “That’s IT?!” I shrieked (politely – I’m a very considerate shrieker.) “That’s all I get to eat? That’s not even a whole meal at T.G.I.Fridays! I’ll never get another Blizzard again! I HAVE THE SLOWEST METABOLISM EVER!!!”

To which he replied, every bit the scientist he was, “It’s not slow. It’s efficient. Your body works perfectly well and is extremely healthy with only half the energy requirements of the average man.” While he was waxing eloquent about my body being a Prius in a world of Hummers, I was trying to come to grips with the fact that at Superbowl Parties there would be nothing super in a bowl for me. I could have one chip with a dollop of hummus while everyone else got Chicago-style pizza.

And then I said it. The phrase every parent hates most: “It’s not fair.”

“Of course it’s not,” he replied simply. “It never is.”

This idea of “deserving” more food has been a real struggle for me as I’ve progressed with Intuitive Eating. In the past I’ve focused endlessly on how to “stoke my metabolic fires” “become a fat-burning machine” and “rev up my engine” so that I could eat whatever I wanted with impunity. So every time I feel my body get full after just a few bites, my mind stomps its foot and cries, “It’s not fair! This food is yummy and I earned it! Everyone else gets to keep eating it! I want to keep eating it too! What if they eat it all and there’s none left for me?!” For whatever reason, talking back to that voice is very difficult for me. Sure I’ll survive the Apocalypse (party with the ‘roaches!) but that’s small comfort when everyone else is snarfing Concession Obsession with abandon.

But the other night I had a breakthrough. There isn’t any point in trying to either speed up or slow down my metabolism. Like Andrew said so many years ago, “Why would I want to fix my metabolism? It’s not broken.” My metabolism may be slow(er) than most but it works great keeping my body running. And you know what? I DO get to eat whatever I want with impunity. I just have to get my wants in line with my needs. When I eat what my body wants (not what my mind wants – that’s different), I don’t feel restricted or left out or unhappy. I just feel good. Even if that means I only eat four bites of a homemade brownie. (And also – who is this “everyone else”?! I don’t know what people eat all day.)

My husband’s fallen in love with this reality show Out of the Wild: the Alaska Experiment where they dropped a bunch of city slickers with no survival skills into the middle of Alaska, gave them a map and told them to make their own way out. On one episode, the biggest and toughest of the men faints from lack of food (seriously, the people who signed up for this show make Survivor contestants look sane) and the voiceover explains flatly that “muscle is expensive” and that women are “better at conserving body mass on less food.” Like the professor said, we’re efficient. Long live the women!

Do you think your metabolism is slow or fast or just normal? Does it matter to you? Do you feel like your body has a set point it wants to stay at? How do you deal with the “It’s not fair, everyone else gets to double-fist artichoke dip while I’m stuck with crudités?” voices??