Major League Baseball players have become overwhelmingly overweight and obese throughout the last 25 years according to researchers.

The prior 100 years saw the players with a steady, ‘healthy’ weight between 18.5 and 24.9 on the BMI scale.

David E. Conroy, professor of kinesiology at Penn State, and colleagues analyzed data collected over the last 145 years on the body weight of baseball players.

Around 1991, the researchers report that the average player’s BMI began to rise, and since then, nearly 80 per cent of players now fall into the overweight or obese category.

In general, obesity rates across the US have been rising, but is it counter-intuitive to see the rates reflected in professional athletes?

The data used was taken from the Lahman Baseball Database, a self-reported record taken on their debut year. Although self-reported data is not necessarily as reliable as clinically measured data, the fact that an increasing weight trend exists is still very telling.

Conroy notes, “The data are observational, and raise more questions than they answer,” cautioned Conroy. “BMI can be misleading, because it doesn’t take body composition into account. What kind of pounds are the players adding? Are they mostly muscle or fat?”

It’s worth noting that steroid use was becoming common in the major leagues from the latter half of the 1990s up until 2013 when random doping testing was introduced.

Steroid usage meant that big hitters could bulk-up substantially adding a large amount of muscle mass.

Conroy explained that, “Research exists that shows how having extra weight can help with certain aspects of baseball. The more force a batter can put into the ball, the further it will travel.”

Whilst hitters are putting on a heavy amount of muscle, pitchers are a different story. Because they are less expected to run often, they can put on more fat without it affecting their performance so much, although it can have an impact on their health.

Being overweight can increase the risk of a myriad of health problems, including heart disease and type 2 diabetes. The incidences of both of these conditions are rising across not only America, but the whole of the western world.

Baseball stars are often seen as role models for young people, and seeing them overweight could warp the image of what is healthy in the public’s mind and mitigate the urgency for people to lose weight and look after their health. As athletes, this effect will be even more pronounced as people expect a sportsman to be the perfect image of health.

Conroy said that the research raised more questions than it answered, but they are questions that need to be addressed.

The finding were published in Obesity Research and Clinical Practice.