The Obesity Epidemic - more complicated than diet and exercise

1 billion humans are obese

Today (03/04/2024) is World Obesity Day. A new study in The Lancet suggests that more than 1 billion children, adolescents (BMI >95th age- and sex-specific centile) and adults (BMI >30 kg/m2) live with obesity around the world. 1 Billion!

What contributed to the obesity epidemic? The “Big Two” - diet and exercise - certainly need to be addressed; however, there is more to it ….. and thus was the undertaking of a team of obesity scholars in 2009.

At the time, my academic research was largely focused on childhood obesity given that I was at a Research-intensive (R1) university, and as I like to say the dean and department chair’s hands were around my neck to bring in NIH (National Institutes of Health) federal grant dollars. I had also just published a paper on the secular changes in physical activity, energy expenditure, obesity and metabolic syndrome in youth. Thus, I was invited along with a group of top-notch scholars in obesity research led by Dr. David Allison to co-author the paper Ten Putative Contributors to the Obesity Epidemic. This is a fascinating paper and I encourage to take a read (not light bedtime reading though). I will just summarize the main factors postulated to contribute to the obesity epidemic of the latter part of the 20th century and beyond here:

🦠Immune system and gut microbiome

🧬Epigenetic mechanisms/transgenerational epigenetics

🤱🏾Maternal obesity, excessive weight gain and lifestyle during pregnancy

🤱🏾Intrauterine and intergenerational effects

🧑🏾‍❤️‍🧑🏽Assortive mating

😴Sleep debt

🍼Endocrine disrupting chemicals (BPA, etc.)

💊Pharmaceutical iatrogenesis

🌡️Ambient temperature and global warming

Human weight, body composition and obesity, like other human traits, are part of the multi-faceted complicated human phenotype.