If you suddenly start eating more beans and vegetables (especially broccoli, brussels sprouts and cauliflower), odds are you’ll also start filling up with gas. Another bloat-maker: gum. Often chewed by dieters to help stifle hunger, it makes you swallow more air than normal, which in turn makes you gaseous.

Rx: Before eating gas-inducing foods, take Beano ($15 for 100 tablets, drugstores), which reduces gas by neutralizing the enzymes that cause it, advises Leslie Bonci, director of sports nutrition at the University of Pittsburgh Medical Center. And bid adieu to sugarless gum: The sweeteners sorbitol and mannitol are known to produce intestinal gas.

“I’m tired all the time”

The Journal of the International Society of Sports Nutrition recently reported that people on high-protein diets could exercise for only half as long as they used to before they began their diets. The culprit: low levels of glucose, the body’s fuel. Without a steady intake of carbs, which readily convert to glucose, the body fatigues easily.

Rx: “Women who are really dragging simply need to eat some complex carbs, such as those in whole grains (brown rice, whole wheat breads),” says Melina Jampolis, M.D., author of The No Time to Lose Diet. “Otherwise, they will be less active and lose muscle mass, which causes their metabolism to drop and makes them susceptible to regaining weight.”

“I’m blocked up!”

Constipation is a frequent complaint among women who follow low-carbohydrate diets like Atkins, says Dr. Jampolis. The problem? Diets high in meat and other proteins are usually low in fiber, which is needed to keep the digestive tract working smoothly.

Rx: Take a fiber supplement such as Metamucil every day and drink plenty of water or herbal tea.

“My hair’s falling out!”

If you cut down on calories enormously (which means you’re really running short on essential nutrients), you may start losing some hair in as little as six weeks, says Bonci. A less severe but still deficient diet will cause hair to thin within three to six months.

Rx: “There’s no fast solution, so start eating a well-balanced diet,” says Bonci. Hair follicles can repair themselves in the same time it takes them to degrade: about six weeks.

“My skin is dull”

Women on extended low-fat diets often notice their skin appears to be a little rough or gray.

Rx: If you’re on a low-fat diet, add more fatty acids (a daily omega-3-rich fish oil capsule is OK), which are essential to healthy-looking skin. Hydration also is important to keeping your glow. “If you’re on a high-protein diet, the lack of fruit and vegetables could make you dehydrated even if you’re drinking a lot of water because fruit and vegetables are more than 90 percent water,” says Bonci.

“I can’t fall asleep”

A growling, empty stomach can keep dieters awake.

Rx: “Before bed, drink a soothing tea, like lemon balm, passion flower or chamomile,” Bonci suggests. “It will give you a feeling of volume without the calories.”