Not all fat is bad, but belly fat is more harmful than fat in the arms, legs or buttocks, he said.

Fitness expert John Siracuse said people shouldn't get caught up with numbers.

"I always got people focused on their bodies rather than on a number and make them more aware of their muscle tissue, their shape," he said. "Are they getting stronger? Faster? Can they pedal longer? If you listen to your body more, you will know the symptoms before your body starts to break down. We tend to forget about our bodies and that's when we start getting fat."

Servoss said she can see where a little bit of extra fat could be good for people facing a serious illness, but said the more weight you have, the harder it is on your joints. Excess weight also comes with numerous health challenges, including circulatory problems, high blood pressure and diabetes, she said.

"I think the numbers have their place," she said. "They do give us some reference but it does ultimately come down to how you are feeling, your exercise tolerance, are you able to do the things you love to do without any difficulty?

"That's the kind of thing I should be focusing more on, rather than that my jeans come from the back of the rack rather than the front," she said.