Why Do Millennials Have a Hard Time Staying Thin? For some reason, millennials have a harder time staying thin when compared to older generations. A study published in the journal 'Obesity Research & Clinical Practice' confirms it's harder for today's adults to maintain a healthy body weight. This accounts for similarities in food intake and exercise levels across generations. The study researched the dietary habits of 36,400 Americans between 1971 and 2008 and the physical activity of 14,419 Americans between 1988 and 2006. Adults are now 10% heavier than adults were in the 1980s, even if they have the same diet and rate
of exercise. Professor Jennifer Kuk, York University Proposed theories for this include the increased use of pesticides, preservatives and antidepressants.