If you want to lose weight but find it difficult, you are not alone.

If you have been gaining weight lately, but can’t really explain why, you are not alone.  

And if you think that people in your grandparent’s generation were generally thinner, you are not alone!  

A new study published in the Journal Obesity Research & Clinical Practice found that it is harder for today’s adults to maintain the same weight than it was for adults 20 or 30 years ago, even when all other factors are the same.    

The study examined dietary data of thousands of americans from 1971 and 2008.  They found that any given person in 2006 eating the same amount of calories, protein, micronutrients and fat and exercising the same amount as a person in 1988 would be 10% heavier today than in the 1980s.  

“Our study results even suggest that if you are 25 years old today, you’d have to eat even less and exercise more than those older than you, to prevent gaining weight.” That is what Dr. Jennifer Kuk lead researcher of the study and professor of kinesiology at York University in Toronto, said in her statement to Olga Khazan for the September 30, 2015 issue of the Atlantic magazine.

Clearly the factors that are making it harder for adults today to stay thin go beyond food intake and exercise.  Dr Kuk said that there are 3 factors they are suspecting may be responsible for this generational increase in weight.

  1. “First, people are exposed to more chemicals that might be weight-gain inducing.”  Pesticides and preservative substances in packaged foods may be to blame.   
  2. The second reason Dr Kuk and her colleagues think that the microbiomes of Americans might have changed between the 1980s and now. Scientist already believe that there are types of gut bacteria that make a person more prone to weight gain. Antibiotics used in animals, additives and the proliferation of artificial sweeteners could be major players.  
  3. The third reason may be that “the use of prescription drugs has risen dramatically since the ‘70s and ‘80s. Prozac, the first blockbuster SSRI, came out in 1988. Antidepressants are now one of the most commonly prescribed drugs in the U.S., and many of them have been linked to weight gain.”

There’s a huge weight bias against people with obesity,” Dr Kuk said to Olga Khazan of the Atlantic. Overweight people “are judged as lazy and self-indulgent. That’s really not the case. If our research is correct, you need to eat even less and exercise even more just to be same weight as your parents were at your age.”