After tracking the progress of 1,205 men and women who’d enrolled in an outpatient weight-loss program—which included regular meetings with psychologists, nutritionists and physicians—researchers at the University of Alberta and the Royal Alexandra Hospital in Edmonton found that a whopping 43% dropped out before achieving sustainable weight loss.  And ladies, listen up: Women were the most likely to quit the program early. “These are women who’ve often struggled with their weight for years,” says Daniel Birch, MD, co-director of the Royal Alexandra Hospital’s “Weight Wise” program and the study’s lead author. “They really do want to improve their health, but they give up before they can.” He says there are several factors at play. “Losing weight is about more than a simple physical process,” Dr. Birch says, adding that depression, stress or even underlying medical problems can hamper efforts.  More From Prevention.com: 5 Women Who Lost 100 Lbs—And Kept It Off   So where does it leave those of us with a lot to lose, or even just a little? “The number one lesson for anyone is to manage your expectations,” says Dr. Birch. “People are after this dramatic, rapid weight drop—usually, that just isn’t going to happen.” Your best bet, says Dr. Birch, is that in addition to making your goals realistic, surround yourself with a supportive team—including your doctor, a nutritionist, and maybe even a psychologist.  “I wish we had an easy fix,” he says. “But to reach a healthy weight, the investment of time is well worth it.”   Not sure where to start? We’ve got you covered with The End Of Dieting.   Follow her on Twitter: @katiedrumm Send news tips and positive vibes to: Katie.Drummond@rodale.com