BOSTON (CBS) – This is the time of year when many people are excited to get in shape and eat healthier. The problem is many people are going too far. A dangerous phenomenon called “Orthorexia” is becoming more prevalent.

Personal trainer Bron Volney at Boston Sports Club is just as concerned with his clients’ diet as he is with their workout.

“I monitor a lot of my clients’ weight, and if they are dropping really fast, and it seems they are going to extremes, you’ve got to question them and say, ‘Let’s make sure you are staying healthy,’” said Volney.

Staying healthy means following a balanced diet. A growing number of people, however, are eliminating entire food groups, seeing only negative qualities in things like dairy, eggs, meats, grains, and fats.

Over time, the only things left in their diet are fruits and vegetables.

Taken to an extreme, it’s now treated as an eating disorder called “Orthorexia”.

This is how Boston University Nutritionist Jenn Culbert defines Orthorexia: “What it essentially means is that someone is obsessed with eating only healthy food that they consider to be pure.”

The problem, according to Culbert, is our bodies need those so called bad foods. (Continued…)

“Fat helps us absorb fat soluble vitamins, A, D, E, and K, and it also helps us absorb phydo chemicals in fruits and vegetables,” said Culbert. “Whole grains have been shown to be heart healthy. . . Dairy is a great source of protein and a great source of calcium and Vitamin D.”

Orthorexics start with the best motives, really wanting to be in great shape and good health. The problem is their actions have the exact opposite effect.

Caitlyn Bryne is very conscious of her diet when she works out with Volney at the Boston Sports Club near Government Center.

She said when she first started working out and trying to lose weight, she was a bit extreme in her approach. “It’s hard because you have to train yourself to eat well. It was hard for me.”

She added that it wasn’t realistic and certainly wasn’t fun.

Culbert says the warning signs are not hard to spot. “When you are no longer able to enjoy any of the foods that you once did, and you are no longer able to participate in a family meal, or going out with a friend.”