In the fifth and final installment of our week-long series on diet and fitness trends, we took a closer look at the benefits and consequences of taking diet and fitness programs to the extreme.

There may be dangers to taking diet and fitness to an extreme. (Comstock, ThinkStock)

Eating healthy makes us feel better, sleep better, get the nutrients we need, and allow our bodies to function as they should, according to Lynn O'Hara, MS, RD, LPC, a Licensed Psychotherapist and Registered Dietician in Bay Head, New Jersey. However, she cautioned, following a restrictive diet for a certain amount of time and losing weight is a plus, until you slip back into unhealthy eating habits and end up gaining all of it back.

"So if you can't live with what you're doing or find some sort of happy medium, then you're not going to achieve success," O'Hara said.

While very restrictive dieting can lead to eating disorders, extreme clean eating or eliminating all processed foods and extra additives from your diet, it can have a negative impact as well, according to Jamie Hanley, a licensed associate counselor and Eating Disorder Therapist at GenPsych in Brick Township, New Jersey.

"The clean eating stuff can become so rigid that it turns into what's called orthorexia, which is an eating disorder where people are obsessed with eating healthy," Hanley said. She added the problem is when people really get stuck in good and bad foods, "Then you miss out on enjoying life."

Working-out produces feel-good, chemical endorphins that can improve our mood and reduce stress.

"Exercise if phenomenal in helping us to keep our bodies healthy, keep them running regularly, to diminish anxiety and to help us sleep well at night. There is no better anti-anxiety than moving our bodies," O'Hara said.

Like extreme dieting, however, too much exercise also can be unhealthy.

"When exercise is taken too far, it can turn into exercise addiction," Hanley said.

The endorphins people experience post-exercise can be addicting.

"They put exercise as a priority above everything else, and it really gets in the way of your life. It becomes disruptive to daily life activities," Hanley said.

Extreme exercise also beats our bodies into submission, Hanley said.

"Our body reacts by eliciting the stress response and cortisol is part of that, and it holds onto fat, so we won't lose weight," she said. "If you can find pleasure in whatever exercise you chose, if you can find pleasure in the foods that you eat, and you can do that in a relaxed state, then your body will enter the relaxation response and be able to absorb the nutrients you need and release the weight that you don't need."

O'Hara said Americans can seem like a motivated population when it comes to dieting and exercising, but "67 percent of us are overweight. So, is it really motivating us? I don't know."

O'Hara she sees clients weekly who she said are trying to work through all of the issues they have in trying to stop compulsive dieting and compulsive exercising because they're hurting their bodies.

So what motivates us then to continue to follow the latest diet and exercise trends?

"I think that society has an unrealistic view of what people should look like," O'Hara said.

She said commercials on television seem to portray thin, young attractive women, while showing a variety of men.

"We as society hold an image in our heads that may be very unrealistic for us to achieve, yet we keep trying to go for it," she said.

Hanley also blamed the media and the way products are marketed for playing into people's insecurities.

"Regular people don't have access to resources that celebrities have," Hanley said, also pointing out that images of celebrities, who have access to personal chefs and trainers, or images that have been Photoshopped, are not realistic.

Emotional issues also can fuel compulsive dieting and compulsive exercising.

"Those things aren't going to stop until they work through whatever the emotional reasons are," O'Hara said.

Click below to read the previous articles in our "Fitness Trends" series: