#Sia Cooper is becoming a celebrity in the fitness world. On her YouTube channel, she's inspiring viewer with her 40-lb weight loss. But the "Fit Mom" blogger's health habits before having kids weren't so great. In fact, her diet and exercise lack were so spectacularly bad that she was showing signs of early aging. And it was looking 40 at 20 that spurred her to shed weight. Even with a two-year-old and eight months pregnant, Sia was thinner and in better shape than before having kids. Critics attacked the young mom saying she was hurting her baby with extreme pregnancy fitness. Just a few months after birthing the second baby, Cooper has shed baby weight in a healthy way. Here's how. 

Behind weight gain lurks fast food

Internet sensation Sia Cooper blogs on "Diary of a Fit Mom" that as a college student, she lived on junk food, mostly quick takeaway. Burger King and Chick-fil-A were her addictions of choice, but none of the fast food chains are great. Behind every great behind is a history of fast food consumption. Inside belly fat can be found copious amounts of burgers, fried chicken, pizza, tacos, wings, pop, fries and shakes. Subway might be a better option but have you ever read the calorie count in the bread alone? And how many people really order from that reduced calorie menu and how many go for the triple cheese meatball supreme?

Premature aging

So Sia, like so many other young people, could eat that junk food for a while. But even at 20 it was taking its toll in early aging. She was tired, lethargic and had no energy for exercise. That trifecta of MSG, trans-fat and empty calories in fast food will do it (as Morgan Spurlock found on "Supersize Me"). Cooper was starting to feel old before her time and it scared her. If she felt like 40 in her early 20s, what would she be like at 40? Another wake-up call was watching "Food, Inc." and seeing the horrific way corporate farms manufacture food and the lack of nutrition inside Big Food. 

Do it for the children

Cooper shed 40 pounds but she also toned up. Some folks think she's too extreme. She actually had abs even when she was 32 months pregnant. Cooper defended it saying that obesity is the real danger and her health regimen helps her kids. Her reason was to be healthy for and also with her children. Childhood obesity is directly linked to maternal weight. Type 2 diabetes, hypertension, liver and heart problems, cholesterol issues and a host of other obesity-related lifestyle diseases grow in the womb. #Celebrities #Weightloss