While exercise is usually associated with weight loss, it’s not the only way to trim extra pounds.

According to a Fortune Magazine article published in March, diet is also an important aspect of weight loss. A meta-analysis found similar results. Weight-management programs that incorporate exercise with diet can lead to more constant weight loss over a year than either diet or exercise alone.

Another study shows an increase in percentage of people who are physically active from 2001 to 2009. However, the percentage of Americans who were obese also rose. The problem comes from food choice.

To prepare for his hockey season, senior Brian Moody decided to start a diet. Instead of eating excess calories, he focused on vegetables and lean meat, like chicken and steak. Moody said this gave him more energy to continue exercising.

“I knew that I needed to get bigger for the hockey season coming up, so I decided to eat healthier, and that really helped me, too, when it came to getting bigger and stronger, and also gave me more energy so I could go to the gym more,” Moody said. “It ended up allowing me to gain more muscle mass, get a little bit bigger and definitely made me a little bit stronger.”

Although registered dietitian Julie Johannsen-Wilk, who works at St. John Hospital & Medical Center, said teenagers can diet, she recommends they see a dietitian before starting.

“The best way for teenagers to lose weight is to control their carbohydrate intake and to make sure they have a protein source and or healthy fat source with each meal,” she said via email. “Watch portion sizes. Scheduled meal times (are) also important.”

According to studies in the monthly journal Obesity Reviews, people in exercise programs ended up burning less energy with exercise than anticipated and boosting their caloric intake.

Because exercise increases appetite, physical education teacher Bruce Bentley said keeping track of calorie consumption in a journal is beneficial. He also said gradual weight loss is important.

“For behavioral modification, instead of taking a big plate, eat on a small plate,” Bentley said.  “A lot of it is psychological, too.”

Diets with controlled carbohydrate intakes, protein and fat sources with each meal, scheduled meal times and portion sizes are beneficial, Johannsen-Wilk said. In addition, for a dieting to be effective, teenagers should eat breakfast, eat meals every four to five hours and snack two and a half hours in between, twice a day.

“Teenagers are growing and a bad diet can cause problems with growth and development,” Johannsen-Wilk said. “A bad diet is any diet that eliminates any of the macronutrients: carbohydrates, proteins and fat. We must have all three. Another bad diet is one too low in calories or too restricted or limited in foods.”

However, there is a limit to exercise while on a diet.

“The negative effects are losing weight too fast, which results in our bodies breaking down muscle or tissue for energy, which results in taking away metabolically active tissue,” Johannsen-Wilk said. “Then when you go off the diet, because you can’t live on this forever, you gain fat back, which in the end lowers your metabolism.”

Although too much exercise isn’t healthy, just the right amount can boost immunity from diseases. According to the Academy of Medical Royal Colleges, physical activity is a “miracle cure” because it decreases an individual’s chances of getting musculoskeletal disorders, cardiovascular disease, diabetes, pulmonary diseases, neurological diseases and depression.

Johannsen-Wilk and Bentley both recommend teenagers exercise 20-30 minutes a minimum of three to five times a week. Bentley emphasizes cardiovascular exercise.

“Make sure you get some exercise in a given week, and hopefully cardiovascular is better,” Bentley said. “In certain sports, you’re going to lose more calories than you would doing something else.”

Moody said he tries to keep a balance between exercise and diet to reduce negative results.

“If I am not working out while playing hockey, I go down in weight, and it’s hard to build it back up,” he said. “That is when I have to start eating healthier and doing stuff like that to get back to where I was.”