The Silence of the Slims

By Scott Charles Anderson

Perfect people are the scariest people to me. — Leslie Mann

Slim model

Completely different.

And so it happened that all the tall people got together and started to belittle the short people. They wrote articles about how shortness was preventable: just keep reaching up and you could be taller too! It was such an obvious and easy fix that tall people became disgusted by the shorties, who clearly had shabby moral character. After all, tall was vastly superior and if you weren’t stretching yourself, who was to blame but your short lazy-ass self?

Unfortunately, this silly fable is not far from the truth: try to be a runway model if you’re under 5’9”. But if tall models started impugning the character of shorter people, there would be a deafening twitterstorm over it. And yet, this exact reasoning is used everywhere when we talk about fat people versus skinny people. How many times have you heard that fat people just need to control their portions, count their calories and take the stairs? And yet, there is no more basis for this skinny philosophy than for the fabulist tall philosophy. If you won the genetic lottery, and you’ve always been lean, goody for you. It’s nice to be born perfect. But it doesn’t make you an expert on obesity.

It’s an epidemic

The problem is that since the 1980s, our rates of obesity have ballooned and any dummy knows that the calories you eat minus the calories you expend will be turned to fat. But which skinny person is computing that math with every mouthful and every prance? Not one! They don’t need to, because they are functioning correctly: a tiny part of the brain called the hypothalamus is doing that job with such precision that in normal people, not one cookie goes down without being properly metabolized. If you think you’re slim because you actually monitor your food, I call bullshit! You can’t possibly know the actual caloric content of a single mouthful, let alone a lifetime of them. You let your hypothalamus do that for you.

Big people are stereotyped as lazy gluttons, but they are often the ones who are counting (and cursing) their calories, worried about every bite. Unfortunately, calorie counting rarely works. Only one in twenty people can actually keep weight off after a diet. It’s depressing as hell, even if other people were on their side, which they aren’t.

Being overweight is a nasty problem. As well as acting as a magnet for the opprobrium of all your righteously slim friends, being overweight leads to lower income and, often, worse health. The number one reason for a bully to pick on you? Being fat. Reddit, until recently, had a whole section on fat shaming. Fat people have an entire genre of jokes devoted to them alone. Even doctors don’t like fat people! The head of the Cleveland Clinic, Dr. Delos Cosgrove, has said that if it weren’t illegal, he would refuse to hire fat people. All in all, there is no lack of motivation to lose weight. It’s a constant drumbeat of derision.

So, what’s the problem?

Kalahari Bushman

This is how raw nature sculpts a man. Where did we go wrong?

Why is it so hard to lose weight? What has changed in the world to spawn this epidemic? A scattering of hunter-gatherers still living in Africa provide a glimpse into what nature originally intended. These lean people weigh the same at death as they do at 18. Their hypothalamus performs perfectly throughout their life, making them hungry when they need food and stopping them when they’re full. If they eat a few excess calories, it increases their metabolism to burn them off. It acts as an adipostat, keeping body fat (adipose tissue) within a narrow range and helping to keep weight at a static setpoint for an entire lifetime.

Admonishments to control portions or eat fewer carbs are simply not necessary for these gracile people. No one nags them to exercise more. No one tells them anything, because it is all under natural control. Billions of years of evolution have fine-tuned this basic adipostat to perfection.

If nature has provided such an explicit signal, how are we missing it? Is there something wrong with the self-control of overweight people? In a land of fast food, are we racing through the red lights? We know that you can lose weight if you simply deprive yourself, so why don’t fat people just make up their minds to starve a little? The lean would have us believe it’s mind over matter, but if it’s all in your head, how do you explain the wild success of bariatric surgery? This surgery isn’t a lobotomy; it doesn’t touch the brain. But it works: the weight just melts off. Does it correct their moral turpitude? Or is something else going on?

It’s not all in your mind

What is wrong with all the overweight people around the world? Researchers have found genetic components to some kinds of obesity, and that is a partial explanation. It’s hard to think yourself out of a genetic condition. For instance (going back to our opening fable), try to get tall by stretching. Okay, you can gain an inch or two on a rack, but you tend to shrink right back down again.

Some other fascinating connections are coming from microbiome research. Your microbiome quickly adjusts to novel nutrient streams (created by mad food scientists) such as Doritos and Twinkies. Sugar and carbs have largely replaced fats in our diets, and this has had unintended consequences, possibly leading to the rapid rise in insulin resistance and type 2 diabetes that are unwelcome fellow travelers with obesity. Might all of this have a microbiome connection?

Fat Pig on antibiotics

I believe the antibiotics are kicking in.

The dramatic rise in the use of antibiotics in animal farms over the past 50 years has had a direct impact on the microbiome. People are rightfully worried about antibiotic resistance from this practice, but a more damning connection comes from the real justification for antibiotics: They aren’t meant to treat sickness, they are actually growth promoters. Farm animals develop faster on low levels of antibiotics, allowing them to come to market earlier and fattening profit margins. This trick seems to work on all animals, including humans. There’s an inescapable chain of logic here: we’ve been the unwitting subjects of a vast experiment to fatten all the animals on the planet. It has been a huge success.

But the antibiotic story doesn’t end there: Americans are major consumers of medical antibiotics. We use them when we have bacterial infections (which works), and we use them on viral infections (which doesn’t). They are so easily available that, when your baby is crying, it’s hard to resist the compelling magic of antibiotics, useful or not. This capricious habit has taken a toll on our gut microbiome. Each dose of antibiotics kills billions of useful bacteria in the gut, and it can take weeks, months or even a lifetime to recover.

A recent study has shown that intermittent doses of antibiotics can radically alter your gut bacteria, leading to excess weight and obesity. Today’s antibiotics are broad-brush drugs that decimate the good bacteria with the bad. Until we can develop better-targeted antibiotics, we may be doomed to wreck our gut with each dose. After a lifetime of this, we may have done permanent damage.

Your first birthday present

Your starter microbiome was a birthday gift from your mother. It came through her placenta, birth canal and milk. If you got a good batch of bacteria, you’re golden. Researchers can’t be specific about which collections of bacteria are primo just yet. There may be hundreds of different microbiome collections that are beneficial, each mixed and matched from thousands of available microbial species. That sounds complicated, but I’m actually simplifying here … the reality is far messier.


What kind of bacteria do you have?

A good microbiome will get trained over the first two years of your life and then will start to take over, talking directly to your brain, via your hypothalamus, helping you decide what and how much to eat. For people like hunter-gatherers with diverse bacteria, their microbiomes provide reasonable feedback to the hypothalamus and their setpoints never budge. But even the sweetest microbiome can sour with sufficient antibiotic treatments.

A damaged microbiome may run hot, allowing a few hi-octane bacterial species to rule the gut. These gluttons place incessant orders for more fat and sugar. They can disturb your mood, affecting other parts of your brain. The hypothalamus tries to make the correct adipostatic decisions, but the incessant whining of your microbiome may be able to override its better judgement and allow that fourth piece of pizza. Note that all of these decisions are motivated by the gut. You can override them (if you even notice them), but you only have a limited amount of veto power. A bad gut can ruin your life.

Credit where it’s due

And so, it is probably time to admit that some of our expanding girth is beyond our ability to control. The ones who are valiantly trying to fight the fat, counting calories and forcing themselves to exercise more – even while carrying excess weight – are the ones to champion. They are trying like their lives depend on it.

The ones to jeer are the ones who lucked into a happy group of bacteria in their gut, yet somehow feel that qualifies them to offer advice about weight loss. You know who you are. You, the smug slim, are not adding anything useful to the conversation, so your silence is appreciated. Many thanks.


Klein, D., J. Najman, A. F. Kohrman, and C. Munro. “Patient Characteristics That Elicit Negative Responses from Family Physicians.” The Journal of Family Practice 14, no. 5 (May 1982): 881–88.

Puhl, R. M., J. D. Latner, K. O’Brien, J. Luedicke, M. Forhan, and S. Danielsdottir. “Cross-National Perspectives about Weight-Based Bullying in Youth: Nature, Extent and Remedies.” Pediatric Obesity, August 1, 2015, n/a – n/a. doi:10.1111/ijpo.12051.

Dibner, J. J., and J. D. Richards. “Antibiotic Growth Promoters in Agriculture: History and Mode of Action.” Poultry Science 84, no. 4 (January 1, 2005): 634–43.

Jeurink, P.V., J. van Bergenhenegouwen, E. Jiménez, L.M.J. Knippels, L. Fernández, J. Garssen, J. Knol, J.M. Rodríguez, and R. Martín. “Human Milk: A Source of More Life than We Imagine.” Beneficial Microbes 4, no. 1 (March 1, 2013): 17–30. doi:10.3920/BM2012.0040.

Norris, Vic, Franck Molina, and Andrew T. Gewirtz. “Hypothesis: Bacteria Control Host Appetites.” Journal of Bacteriology 195, no. 3 (February 1, 2013): 411–16. doi:10.1128/JB.01384-12.

De Lartigue, Guillaume, Claire Barbier de La Serre, and Helen E. Raybould. “Vagal Afferent Neurons in High Fat Diet-Induced Obesity; Intestinal Microflora, Gut Inflammation and Cholecystokinin.” Physiology & Behavior 105, no. 1 (November 30, 2011): 100–105. doi:10.1016/j.physbeh.2011.02.040.

Nobel, Yael R., Laura M. Cox, Francis F. Kirigin, Nicholas A. Bokulich, Shingo Yamanishi, Isabel Teitler, Jennifer Chung, et al. “Metabolic and Metagenomic Outcomes from Early-Life Pulsed Antibiotic Treatment.” Nature Communications 6 (June 30, 2015). doi:10.1038/ncomms8486.

2 thoughts on “The Silence of the Slims

  1. I tend to agree with you that the stability (or depleted state) of one’s microbiome is likely to turn out to be a major factor in weight loss (or the lack of weight loss), but I’m more optimistic that this can be overcome. Changing the microbiome is certainly difficult, and its complexity continues to elude us, but sophisticated diets and scientifically validated complex probiotics (i.e. mixtures of more than one or two or a dozen species) may ultimately exploit the knowledge we don’t yet have.

    • Steve, I think you’re correct: we will figure out an appropriate microbiotic solution. We’ve seen fecal transplants cause obesity, so we know there’s a connection. And there are some bacteria known to be associated with leanness. We’ll figure this out, but until we quit dosing ourselves with broad-spectrum antibiotics, we may continue to lose the race!

Leave a Reply to IFdiet (Steve Mount) Cancel reply

