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Dear friend, so your doctor says to go on a diet…

HAES expert Lindo Bacon, PhD teaches an introductory nutrition course at City College of San Francisco. They recently assigned an essay to students, asking them to write a letter to a friend whose doctor recently informed her that she is obese and encouraged her to diet. Student Molly Breen generously agreed to share her “A” essay.


Dear Pat,

It sounds like you had a pretty upsetting visit to the doctor, and the first thing I want to do is give that guy a kick in the pants! I don’t think he’s giving you good medical advice, and I definitely don’t think he should have made you feel bad about your weight or your body. I find his suggestion that you “just try a little harder” to lose weight especially infuriating, since I have never in my life met someone with more willpower and self-discipline than you.

But I know you didn’t write for a pep talk. You wrote because you know I’m taking a nutrition class this semester and you want my advice on losing weight. Well, here’s my advice: I don’t think you should lose weight. For one thing, you’re gorgeous, and for another, I don’t agree with your doctor that body fat is necessarily dangerous to your health. However, I do believe dieting is dangerous, to both your physical health and your spirit. 

I know, the doctor said you were obese and pointed to the scary number on the BMI chart and told you about all the diseases you’re at risk for, but I’m not buying it. Who came up with that chart anyway? A bunch of doctors and researchers funded by weight loss drug companies and lap band manufacturers? (Don’t even get me started on those!) And how do they come up with these numbers that affect our insurance rates, our rapport with our doctors and our sense of self-worth? Who knows! Consider this: in June, 1998, the National Institute of Health’s Obesity Task Force adjusted the standards of the BMI. As a result, 29 million Americans went to bed with average figures and woke up ‘overweight.’ None of them had gained a pound, but all were now at “higher risk” for Type 2 diabetes, atherosclerosis, and hypertension.

It’s true that, in general, fat people are at higher risk for these diseases. But there is no evidence that being fat is the primary cause for these diseases. My nutrition teacher explains it this way: there is a well-known correlation between baldness and heart disease in men. But we don’t think the baldness causes heart disease. In fact, the heart disease and baldness are related to high levels of testosterone. In the same way, body fat and diabetes may be correlated, but that doesn’t mean body fat causes diabetes. Fat people may be more likely than thin people to have diabetes because fat people are also more likely to be older, poorer, more sedentary and to lack access to decent medical care and grocery stores carrying nutritious foods, not to mention safe places to exercise and play. There is even evidence that the stress of being told that you look bad/ugly/unacceptable all the time takes a toll on the body and can increase risk of disease.

Now maybe you’re thinking, ok, body fat might not be that bad for me, but I still don’t like the way I look. So give me some diet tips already! Well, I won’t, because diets don’t work. Yeah, I know you’ve lost weight on diets before, and that’s because at first, diets do work. Let’s consider a nice, “healthy,” gradual diet and program of exercise. No crazy cayenne pepper cleanses or hot yoga marathons here — you’re just going to cut back on sweets and start power walking for 30 minutes a day. And let’s say that, on average, you need to eat 2000 calories each day to fuel your body. Suppose those sweets you’ve given up equal 200 calories a day and the walking is burning an extra 200 calories a day. That means you’re using up 2200 calories worth of energy a day, but only taking in 1800. Your body has to get the 400 calories it needs from somewhere, and, yup, it’s going to get them from fat stores.

So you’ve been on this diet and exercise program for three weeks, and you’ve lost some weight. Six weeks pass — still losing weight. You buy a pair of $160 jeans. You RSVP yes to your college reunion.

Six months pass. You haven’t lost much weight in the past month. Nothing about your diet has changed. You don’t even crave sugar anymore, and you’re still exercising. Month seven, you step on the scale and realize you’ve gained a pound. After a year, you’ve regained half the weight you lost in the first five months. Two years later, and you’ve regained it all, plus five bonus pounds. And all this time, you never stopped dieting and you kept up the exercise. And then you go into your doctor’s office, and he tells you you’re obese and need to . . . diet and exercise to lose weight.

I know you recognize this scenario, because we’ve talked so many times over the years about this painful, frustrating cycle. But now I know why you keep gaining the weight back. You know what homeostasis is, right? When you get hot, you sweat to cool down; when you get cold, you shiver to warm up. Your body turns these mechanisms on and off automatically, without any conscious input from you, because it is invested in maintaining a body temperature that allows all its vital functions to go on functioning. It turns out your body is every bit as invested in maintaining a healthy body weight, and will see to it that you maintain that weight whether you like it or not. We all have what’s called a set point, which is really a range of weights at which your body feels comfortable and safe. Get below your set point, and your body wants you to gain weight. Get above your set point, and your body wants you to lose weight. But because back in cave people days there was no risk to having extra body fat (and a lot of benefits!) and a HUGE risk to having too little body fat, the mechanisms that prevent you from losing weight are stronger in most people than the ones that prevent you from gaining weight. These mechanisms are slow, gradual, and out of your control. For example, your body might lower your body temperature slightly so you burn fewer calories. It might make you a bit more tired and sluggish, so you move less. It might become extra efficient at wringing every last calorie out of every piece of food you eat. And it might make a wider array of foods appealing to you, especially fatty, sugary, calorie-dense foods. Over time, all these small effects add up to you burning fewer calories and storing more, in spite of the fact that you’re still eating less. And the real kicker is, the more you diet, the more conservative your body becomes in terms of its fat storage. “You’re starving me again?” Your body says. “Well, I’d better sock away some more fat to get us through these scary lean times.” By dieting and making your “thrifty genes” even thriftier, you can actually bump up your set point.

So you can see why I think your doctor gave you crummy advice. He’s operating on popular but scientifically unsubstantiated claims about the risk of body fat and his prescription —weight loss— is not only impossible for the vast majority of people to achieve in the long term, but actually leads to increased weight gain and is damaging to health!

 What I really want to tell you, my dear Pat, is to focus your considerable energy on the things that actually impact your health, and let this weight business go. You have so many healthy habits already. You swing dance; you have a million friends; you cook dinner every night; you’ve started using meat – how did you put it? “As a condiment?” You already know what to do. Trust yourself, and trust that bod.

I don’t want you to take my word for any of this. I’ve included a few links to different resources including some info on something called intuitive eating. I also encourage you to check out the counter arguments (a lot of companies stand to gain from the notion that people can lose weight, so they shouldn’t be hard to find!). If you can find studies that support successful, salutary, long-term weight loss for a significant number of the participants, send them to me. We can comb through them together.

I hope this letter answers your question in a way that feels satisfying, or at least intriguing. I totally understand if it also feels annoying, frustrating and upsetting. I don’t for a minute think that what I’m sharing with you is easy to hear. But it is the best advice I know how to give, to someone who deserves nothing but the best.

 Yours in fondness and solidarity,


 Molly Breen is nutrition student, author, blogger, and green grocer at Other Avenues, a food co-op in San Francisco.

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