Losing weight both safely and effectively are the keys to any diet plan, doctors and nutritionists say.

A weight-loss rate of 4 to 8 pounds per month is "probably very safe for most people," said Dr. Michael Hirt of The Center for Integrative Medicine in Tarzana.

Dr. Karl Kaplan, a physician and nutritionist who directs Weight Wise Medical Weight Management on the campus of Valley Presbyterian Hospital in Van Nuys, pointed out that though 400-calorie diets were once used under doctors' supervision in the past, they have been found to be much too dangerous to use.

"Under 300 was considered essentially a starvation diet," he explained. "They would lose a disproportionate amount of protein, they would have disturbances in their electrolytes, get very low potassium (putting patients' hearts at risk). And with the original liquid collagen diets, people died."

Low-calorie diets in the range of 800 to 1,200 calories per day are considered safe if followed under a doctor's supervision. And weight loss should be limited to no more than 1 percent to 2 percent of an individual's weight per week, said Kaplan.

For the obese, he favors a doctor-supervised plan of calorie cutting and starch avoidance, specifically excluding bread, tortillas, rice, potatoes, pasta, popcorn, cake and cookies, though he pointed out that these recommendations aren't universal.

Though Kaplan doesn't use the Atkins plan, which calls for more sweeping carbohydrate avoidance, he does appreciate the late doctor's success in "rattling the cage" of conventional medicine's approach to nutrition.

Hirt takes a somewhat different approach, changing plans to fit individual dieters.

"I believe that there is no one diet for all America," said Hirt, who prefers plans mapped out with patients in consultations. "I don't believe that everybody can read the same book and get the same results, because people like to eat different foods."

Three common habits of successful weight-losers, according to Hirt:Weighing in each day: "That allows them to keep track."Eating breakfast daily: "Studies have shown that people who skip breakfast eat 27 percent more calories in a day than people who don't." The hunger pangs and ill feeling that can follow skipping the first meal can set people up for poor food choices later in the day.

As Kaplan points out, the risks of being overweight range from diabetes and its associated conditions, such as increased risk of heart disease, to high blood pressure, high cholesterol, acid reflux and orthopedic problems."Of the top 10 things that kill people in this country, nine of them are related to what you eat," said Hirt.