TEMECULA -- It's doubtful that Alan Winkelstein will ever be a loser. But hopefully, he will be slimmer.

The Temecula optometrist began his yearlong journey on Friday to lose 100 pounds in a charity weight-loss challenge to benefit the Boys & Girls Clubs of Southwest County. He's hoping to raise $100,000 worth of sponsorships as he drops the pounds.

The five-foot, eight-inch Winkelstein stepped on a scale Friday afternoon at Temecula Valley Fitness for the official weigh-in: 299 pounds.

"I'm fairly healthy now, but I'm not always going to be unless I make changes," he said. "I can't see how it can't catch up with me."

Winkelstein, 48, has been a Temecula resident since 1990, the same year he started his Temecula Valley Optometry practice. He says he has struggled with weight all his life, hitting 350 pounds at one point.

While he hopes to help the Boys & Girls Clubs -- of which he has been a board member since 1991 -- with an infusion of funds, Winkelstein also plans to use his own story of weight struggles to reach out to children who may be facing the same issues he faced as an overweight kid.

"It's hard always being picked last for a team and being passed over," he said. "It just seems when you are overweight, you always have to prove yourself."

He said those problems continue into adulthood and followed him in his career.

"(Weight) affects things in a lot of areas of your life, sometimes at work you just get overlooked. It's not fair, but that is how it is," he said. "It's been difficult dealing even with my own patients. It's hard for me to tell them that they need to be concerned about their weight when I'm in the same situation."

Weight loss has been in the national eye since 2004, when "The Biggest Loser" debuted on NBC. On the show, significantly overweight contestants are encouraged to drop pound after pound by changing their diet and hitting the gym. Contestants weigh in each week and see how their efforts have paid off.

"The show is very inspirational to me," Winkelstein said.

An estimated 66 percent of U.S. adults are either overweight or obese and 17 percent of children and adolescents ages 2 to 19 years are overweight, according to the 2003-04 National Health and Nutrition Examination Survey.

Obesity is a major risk factor for cardiovascular disease, certain types of cancer, and type 2 diabetes.

Scott Dickey, a co-owner of Temecula Valley Fitness, said that when Winkelstein approached the gym owners about the fundraising idea, they didn't hesitate to become a sponsor.

"We thought it was fantastic," Dickey said. "To lose about two pounds per week is very attainable, especially now that he has everyone behind him supporting him."

Kathy Engstrom -- the director of Thin and Healthy, a national weight loss program operated at Temecula Valley Fitness -- has been friends with Winkelstein for years and will be his personal trainer as he works to lose weight, offering exercise and nutritional guidance.

"I know Alan can do this," she said. "And I am so excited that he is doing this. Obesity is the No. 1 health problem that our nation faces today. Not only for adults, but for children."

Obesity is defined as a body mass index of 30 or greater, according to the Centers for Disease Control and Prevention. Body mass index is calculated from a person's weight and height and provides a reasonable indicator of the amount of body fat.

Engstrom said the best advice she can give to a person looking to lose weight and get in shape is to partner with someone else, either with a personal trainer or friend. Don't go it alone.

"The best thing for a person to remember -- the No. 1 thing you need -- is patience. That weight didn't come on overnight, and it is not going to come off overnight," she said. "But always stay positive and never, ever give up on yourself."

Winkelstein will be documenting his one-year weight-loss mission through a blog, which will soon be accessible through links at www.thinandhealthytemecula.com and www.bgcswc.org.

"Alan will be able to give members (of the Boys & Girls Club) updates and educate them on his weight loss," said Michele Arellano, executive director of the Boys & Girls Clubs of Southwest County. "People can go through the journey with him."

Arellano said the money raised by the weight loss challenge will go to youth fitness programs such as Triple Play, which emphasizes good nutrition, regular physical activity and overall well-being.

Winkelstein already has decided what he wants to do at the end of his journey when, if all goes according to plan, he will weigh 199 pounds. He wants to be able to buy regular clothes at a regular store, he said.

"I just thought this was the time in my life when I was going to lose some weight," he said. "My goal is to lose 100 pounds and raise $100,000. I know I am going to be able to do this."

For more information on Dr. Wink's Charity Weight Loss Challenge or to make a pledge, contact the Boys & Girls Clubs of Southwest County at (951) 676-6800 or go to www.bgcswc.org.

Contact staff writer Nicole Sack at (951) 676-4315, Ext. 2616, or nsack@californian.com.