It’s Not Your Fault: Your Brain Is Making You Obese

Nearly half of American adults are now obese, and the number keeps climbing. We’ve blamed fat, then carbs, then calories, then willpower. We’ve done low-fat, low-carb, points, fasting apps, and meal kits. And through it all, we’ve kept getting fatter. Perhaps we’ve been blaming the wrong organ!

Follow the Experts

Earlier this month, at the European diabetes meeting in Milan, the obesity field showed its hand. Novo Nordisk presented brain scans of patients taking CagriSema, one of the newest weight loss drugs using a GLP-1 agonist: less hunger, fewer cravings, less of what researchers now call “food noise” — measurable changes in how the brain responds to high-calorie food cues. Lilly’s retatrutide achieved an average weight loss of 28.3% at 80 weeks. The most powerful anti-obesity drugs ever developed don’t primarily work on the stomach or the fat. They work on the brain.

I’ve spent thirty years measuring the body composition of more than 18,000 patients, and I arrived at the same conclusion from the opposite direction — no drugs required. When it comes to fat storage, the brain calls the shots.

A New Disease Model

I call the condition CARB syndrome — Carbohydrate Associated Reversible Brain syndrome. Here’s the idea in plain language: years of eating ultra-processed foods, loaded with the deadly triad of excess sugar, high-glycemic carbohydrates, and omega-6 fatty acids from vegetable oils, gradually deplete the brain’s key neurotransmitters — including dopamine, norepinephrine, and serotonin. These are the chemicals that regulate mood, impulse control, and, crucially, appetite and craving. When they run low, the brain does two things: it drives relentless cravings for sweet and starchy food — the very foods that caused the problem — and it shifts the body into a famine-protective metabolic mode where excess fat is stored at virtually any level of caloric intake. I’ve cataloged up to 22 brain-dysfunction symptoms that travel with this pattern, overlapping with conditions from depression to ADHD to eating disorders. Harvard researchers Hudson and Pope identified the same cluster of disorders decades ago, which they termed Affective Spectrum Disorder (ASDD). They proposed that 14 different conditions were somehow connected, but they never found the trigger or pathology of ASD. I believe the trigger is dietary, and the pathology is identical to that of CARB syndrome.

This is why diets fail, and why it was never your fault. A diet asks your willpower to overrule your brain chemistry. But willpower is a higher-order brain function, and it’s one of the first things to go when neurotransmitter levels run low. Telling someone with CARB syndrome to “just eat less” is like telling someone with poor eyesight to squint harder.

Prevent or Reverse the Disease

Here’s the part the drug companies won’t put in their press releases: the R in CARB stands for reversible. If depleted neurotransmitters are the problem, then removing the foods that deplete them — and restoring the brain’s chemistry — is the way back. In my practice, patients who eliminate ultra-processed foods from their diets don’t just lose cravings; the entire downstream cascade begins to normalize. No doomed diet, no risky pharmaceutical, no surgery.

To be fair to the new drugs: the trial numbers are impressive, but they’re company-presented, the drugs are still investigational, and nobody has answered the most important question — what happens when you stop taking them? A treatment you can’t stop is a treatment you rent. All medications have side effects, some of which can be serious.

So here’s where things stand. The field spent decades telling you obesity was a character flaw or an arithmetic problem. Now their own brain scans say otherwise. The question is no longer whether the brain drives fat storage. The question is what’s driving the brain — and what we’re going to do about it.

I believe I know the answer. And it starts with understanding that it was never your fault.

Diagnose and Treat Your Own CARB Syndrome
If any of this sounds familiar, start with the 22 symptoms of CARB syndrome — and consider whether they describe you or someone you love. Then commit yourself to the following 10 steps to prevent or reverse CARB syndrome:

1. Consume a healthy, whole-food diet with minimal or no ultra-processed food.
2. Try intermittent fasting, restricting food intake to an 8–10-hour window each day.
3. Exercise regularly, including both aerobic exercise and strength training.
4. Take a neurotransmitter precursor, such as CARB-22, to maintain optimal levels of these essential chemicals. Start with one or two capsules twice daily on an empty stomach and titrate up to four capsules twice daily based on your symptoms. If any cravings persist, add more L-glutamine, a safe and inexpensive supplement.
5. Consume products containing the artificial sweetener Allulose, which acts like a weak GLP-1 agonist.
6. To reduce chronic inflammation in your body and brain, take a high-quality omega-3 supplement to get your AA/EPA ratiobetween 1 and 3. I take OmegaRx from Barry Sears of Zone Diet fame.
7. Get 7-9 hours of restful sleep every night.
8. Expand your social circle.
9. Consider meditating on a regular basis.
10. If you already have or plan to use a GLP-1 agonist, stick with a low dose and gradually taper off it once you have followed the above steps.

FAQs

What is CARB syndrome?

Carbohydrate Associated Reversible Brain syndrome (CARB syndrome) is a proposed disease model that suggests ultra-processed foods may contribute to brain dysfunction and overlapping neurological and psychological symptoms. The concept aims to explain potential connections among dietary factors, metabolic disorders, and common brain disorders.

Can CARB syndrome explain obesity, metabolic conditions, and brain disorders?

One of the model’s central aims is to explain possible connections among obesity, metabolic dysfunction, and common brain disorders. The author believes this framework could help explain overlapping health problems. Whether it provides a valid, unified explanation remains an open scientific question, but using the model to benefit individuals’ health appears to be very inexpensive and low risk.

If this is a brain problem, why do I need to change my diet?
Because diet is what damaged the brain chemistry in the first place — and removing the offending foods is the first step in letting it recover. The ultra-processed foods must go before anything else works properly.

How long does reversal take?
It varies. Cravings often ease within weeks of eliminating ultra-processed foods. Full normalization of the symptom cluster takes longer — months, not days. Be patient with a brain that’s been depleted for years.

Can children get CARB syndrome?
Yes, and this worries me most. A child raised on ultra-processed foods depletes the same neurotransmitters while their brain is still developing. You have fairly tight control of what your child is eating, so use that control to reduce intake of ultra-processed foods and focus on whole foods.

Is this just “calories in, calories out” with extra steps?
No. The calorie model says you’re an arithmetic problem. CARB syndrome says your brain is in a famine-protective mode that stores fat at virtually any level of intake — which is exactly why people can eat less and still not lose weight. Fix the brain chemistry and the arithmetic changes.

Where do I start?
Read the 22 symptoms. If they sound familiar, follow the ten steps in the article above: whole foods, no ultra-processed products, the eating window, exercise, sleep, neurotransmitter support, and the rest. It was never your fault — but the way back is in your hands.