Obesity Is Not the Same for Everyone: The Hidden Role of Autism and ADHD in Treatment Response
Why do some patients struggle more than others to adhere to weight-loss programs, even when they are highly motivated?
A new and important scientific review published in Nutrients sheds light on a crucial—but often overlooked—factor: neurodiversity.
The review examined existing literature to understand the relationship between autism, ADHD (Attention-Deficit/Hyperactivity Disorder), and obesity in adults. The findings are clear: ADHD is highly prevalent in adults with obesity and profoundly alters their clinical profile, while autism remains largely unstudied in this population.
1. The Major Gap: Autism and Obesity
The most striking finding from the review is the near complete absence of studies on autism in adults with obesity.
Out of 31 studies analyzed, only two were single case reports, describing successful use of weight-loss medications in three autistic patients.
This represents a major gap. Research in other fields—such as eating disorders—has shown that autistic patients respond better when treatments are adapted to their sensory and cognitive needs (as seen in the PEACE pathway).
It is highly likely that the same applies to obesity, but this research has yet to begin.
2. ADHD Is Over-Represented in Obesity
Unlike autism, the link between ADHD and obesity is well documented.
The review confirms that ADHD is significantly more common among adults with obesity.
One study reported a 20.6% prevalence of ADHD in patients with obesity, compared with 6.8% in non-obese controls.
Prevalence appears especially high in women with obesity.
3. The Clinical Profile of Patients With ADHD and Obesity
Patients with both ADHD and obesity are not simply “patients with obesity.”
They display a distinct clinical profile:
Socioeconomic Status
They tend to have lower socioeconomic status (lower income, education, and employment).
Quality of Life
They report poorer health-related quality of life.
Cognitive & Personality Traits
They show higher impulsivity, cognitive inflexibility, and neuroticism.
They also show lower conscientiousness, self-directedness, and cooperativeness.
Mental Health
They present higher rates of psychopathology, including depression, anxiety, emotional dysregulation, alexithymia (difficulty identifying emotions), and problematic alcohol use.
Eating Behaviors
This is a key area.
Patients with ADHD show significantly higher rates of eating disorders, including bulimic symptoms, binge eating, secretive eating, snacking, intense hunger, food cravings, and food addiction.
They also show lower cognitive restraint, meaning greater difficulty consciously regulating their eating.
4. Treatment Response: What Works and What Doesn’t
The most clinically relevant finding concerns how these patients respond to standard obesity treatments:
Behavioral Programs (Diet + Exercise): WORSE OUTCOMES
Patients with ADHD showed:
Lower percentage weight loss
Lower likelihood of achieving clinically meaningful weight reduction (≥5%)
More difficulty completing program tasks (food diaries, calorie tracking, etc.)
Anti-Obesity Pharmacotherapy: WORSE OUTCOMES
One study found that patients with ADHD experienced consistently and significantly smaller reductions in BMI over five years of pharmacological treatment.
ADHD Pharmacotherapy: BETTER OUTCOMES
In contrast, treating the ADHD itself was associated with successful weight loss.
One study showed:
12.36% average weight loss in patients taking ADHD medications (mostly stimulants)
2.78% weight gain in controls
Bariatric Surgery: COMPLEX OUTCOMES
Bariatric surgery was the only intervention where weight-loss outcomes were comparable to those of non-ADHD patients.
However, this came with important drawbacks:
More post-operative complications
Longer hospital stays
Poorer follow-up adherence
Higher rates of grazing, eating disorders, and self-harm after surgery
Conclusion
This review calls for a paradigm shift.
For autism, urgent research is needed.
For ADHD, the data are clear: patients with ADHD and obesity require an integrated, tailored approach.
Standard behavioral weight-loss programs are likely to fail unless core ADHD symptoms—such as impulsivity and emotional dysregulation—are addressed.
The most effective strategies appear to be:
Direct treatment of ADHD with appropriate medication
Bariatric surgery (but only with intensive psychological support and strict monitoring)
dr Marco Franceschin M.D. Msc.