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Is weight gain really the biggest health epidemic in America – or is weight loss?

That’s the question filmmaker Darryl Roberts raises in “America the Beautiful 2: The Thin Commandments,” as he explores the correlation between being heavy and being healthy, the national obsession with dieting and one common number used to measure health – the Body Mass Index (BMI).

The Center for Disease Control and Prevention (CDC) refers to the BMI as a “number calculated from a person's weight and height” which “provides a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems.”

But according to Roberts, the BMI chart classifieds even some of the most in-shape celebrities and athletes as overweight or obese – including Dwayne “The Rock” Johnson, Mel Gibson, Tom Cruise, Christian Bale, and LeBron James. Roberts is particularly unimpressed that the government, including Michelle Obama, who currently runs the childhood anti-obesity campaign Let’s Move! and encourages BMI screenings for kids, is continuing to use this method as a means to measure our health.

“(Michelle Obama) put on public display how her daughters are getting their BMI checked and was worried about her daughter's weight, so in the movie, a gentleman talked about how it was a shame that the First Lady was using her daughter's weight as a way to push her campaign,” Roberts told FOX411’s Pop Tarts column while promoting the controversial documentary, which is a follow-up to his 2007 film, “America the Beautiful.” “If you see her daughters, I thought it was absolutely ridiculous in the first place. Kids grow in and out of shapes and weights, so to alarm the American public just like that, and to use her daughters to do it, I thought was pretty bad.”

The First Lady Press Office and a representative for Let’s Move! did not respond to a request for comment. But several health organizations beg to differ.

The popular health web site LiveStrong.com acknowledges that BMI does have its limitations, but notes that it is an “important measurement tool.” According to the American Cancer Institute, an “abnormal” BMI exceeding 25 in women with breast cancer is associated with lower survival rates. As BMI during childhood climbs, so does the risk of coronary heart disease in adulthood, according to the American Heart Association.

“America the Beautiful 2” also points fingers at the government for refusing to address issues, such as the possible link between high fructose corn syrup (HFCS) and rising obesity levels.

“Our government (is) blaming us for everything. They're saying we've become sedentary and that are ruining ourselves,” Roberts said. “But I found out that there is a study that shows there's a correlation between the rise in obesity and the introduction of high fructose corn syrup in our food. The government subsidized corn and [it] became cheaper. I'll admit that we are not as active as we used to be, but the government plays a role as well. So I went to D.C. to talk to the Secretary of Health to let her know that you all are in this with us, so can you do your part to stop what you're doing, and hopefully we'll do our part.”

However, Dr. Barry Popkin, who led the 2004 study suggesting that HFCS was largely responsible for obesity, has since admitted he was “wrong to single out” the ingredient, and that its adverse effects were merely speculation. HFCS was also found to be "generally recognized as safe" by the Food and Drug Administration (FDA).

Roberts also learned that “dieting” is no longer just a women’s issue as many males nowadays too are consumed by the threat of creeping over a BMI of 25, and that many dieters in this country have yet to even reach school age.

“The scariest thing I found out is that now five year olds are dieting, and I didn’t even know it existed, but boys with eating disorders,” he continued. “Women have struggled with body image issues for so long, I just got used to the fact that that's just the way it is. But when you're sitting across from an eight year old boy who's going through the same thing, it all just comes crashing down. The eight year old boy started off because his father told him he had 'dunlap disease,' when your stomach 'dunlaps' over your belt. He would go to school and he would get teased about being overweight and he would see everyone else with girls, and he decided he wanted a girlfriend, so he knew he had to be skinny to get a girlfriend.”

Roberts also blames the entertainment industry for perpetuating unrealistic body images.

“Twenty years ago if a woman was to have plastic surgery, she wouldn't tell you, or she would deny it if you suspected it and brought it up. Now, you have so many celebrities on the cover of all these magazines having plastic surgery and admitting to it. It's become so normalized that now teenagers are having plastic surgery parties when they're 16,” he said. “Unfortunately a lot of our youth look up to these celebrities and emulate what they do, and celebrities feel that being thin is their currency and now that's being pushed on us, the American public.”

Roberts hopes “America the Beautiful 2” shows that being healthy – mentally and physically – is achievable without all the unnecessary diets, guides and gizmos.

“I want people to empower themselves to become healthier without worrying about how much they weigh,” he said. “We've become a nation of quick fixes. We want everything now and we want it fast and we don't want to do research or figure things out, so when we don't feel well, we just want to take a pill and feel better. Everything is now and fast and we don't want to work hard for the long term.”

“America the Beautiful 2” is currently playing at select theaters.

- Deidre Behar contributed to this report.