Q. Should you weigh yourself every day?

A. Recent research says it's fine. Frequent self-weighing will not make you depressed, according to researchers at the University of Minnesota. The study published in the journal Preventive Medicine found no strong evidence linking frequent scale-stepping and depression in women. In addition, daily weighing, rather than once a week or month, was associated with lower Body Mass Index levels in women 40 or older. Finally, a study in the Annals of Behavioral Medicine found that daily weighing is helpful "to individuals trying to lose weight or prevent weight gain."

Keeping track of your weight is not just for weight loss. Research from the National Weight Loss Registry has determined that almost all successful weight-loss maintainers have some kind of "5-pound warning system," a way of monitoring their weight before it gets out of control. It could be something as simple as keeping a "thin" pair of pants or a dress rather than getting on the scale, but they all have ways of knowing if they are "slipping" and a backup plan to put into action as soon as they receive their "fair warning."

However, many experts still believe that the average person doesn't need to step on the scale daily. "Weighing daily can lead to an over-reliance on the scale and cause you to obsess about weight. Plus, the scale doesn't indicate when you've gained water weight versus fat weight versus protein and/or muscle weight," says Milton Stokes of the American Dietetic Association. Instead, base your weight on how clothes fit and how you feel, he adds.

Sports nutritionist Nancy Clark agrees. "You should look in the mirror. If you see less fat, you have less fat. Weight fluctuates and can be misleading — perhaps you are constipated, holding water from a sodium-rich Chinese meal, or premenstrual."

In other words, it helps to get on the scale once a week, but climbing on every day may give an inaccurate reading of your progress because of hour-to-hour variations in body weight.

You might be expecting too much too soon and judge the true state of your progress too quickly. Monitoring your weight-loss progress can be like monitoring a stock investment: While it's important to look at yearly returns, checking on your investment every day could give a less realistic picture than taking the longer view. Best advice? Maybe a compromise — three to four times per week.

DESSERT VS. SECOND APPETIZER?

The decision often depends on your mood, says David L. Katz, professor of public health at Yale University School of Medicine.

But, "if all the appetizer options are breaded and fried, and there is a sorbet with berries or a fruit salad option for dessert, then I'll opt for dessert purely for better nutrition. If the first appetizer is a mixed green salad, and the second is grilled shrimp, both your appetizers are quite nutritious and far better choices than cream pie or chocolate cheesecake. While we often think of food choices in categories, nutritional quality really comes down to the specifics," he adds.

CAN WATER REALLY HELP YOU LOSE WEIGHT?

Despite clear anecdotal evidence that drinking water can lower food consumption and alter metabolism, there have been no studies to prove it — until recently. A study from the Children's Hospital Oakland Research Institute found that increased intake of water is associated with "greater loss of body weight and fat." So drink up and lose weight.

TREADMILL VS. ELLIPTICAL TRAINER?

The elliptical trainer is a low-impact exercise machine that's a cross between a stepper and treadmill. Which is better? According to Michael R. Bracko, exercise physiologist and spokesman for the American College of Sports Medicine, "A treadmill is an 'impact' exercise if you walk, and 'high-impact' if you run. If you have lower-body injuries like arthritis in the knees, impact or high-impact exercise is not good for the joints and will prevent a person from achieving fitness goals."

What about calories and muscle building? "If a person is injury-free and can run, he or she will probably burn more calories running on a treadmill versus an elliptical workout. An elliptical trainer is good, too, though, because it works the muscles in a different way. It might be good to exercise on a treadmill one day, then come back the next day and work on an elliptical," Bracko says.

Charles Stuart Platkin is a nutrition and public-health advocate, and author of "Breaking the FAT Pattern" (Plume, 2006). Sign up for the free Diet Detective newsletter at www.dietdetective.com.