It is possible to cut calories and lose weight without constantly feeling hungry and irritable, dietitians say. Here’s how:

• Eat “good” carbohydrates. Healthy carbohydrates boost levels of serotonin, a hormone produced in the brain that boosts mood. Get these nutrients from fruits, vegetables and whole grains.

• Lose weight gradually. Suddenly slashing calories will make you very grouchy. Most people should aim to drop no more than a pound or two a week.

• Go for variety. Your body and brain need foods from each of the major groups — proteins, carbohydrates and fats — to maintain proper chemical balances. Many dieters try to cut out fat; instead, focus on healthy sources such as salmon, nuts, avocado and olive or canola oil.

• Stay away from junk. Sugary foods and drinks create a sudden burst of energy followed by a rapid drop in blood sugar levels. Low blood sugar, in turn, causes irritability, mood swings and problems with focus.

• Eat often. Fasting also leads to low blood sugar levels. Stay on an even emotional keel by eating small portions every four to five hours; never let yourself get too hungry.

• Get enough fiber … This substance, found in plants and whole-grain cereals and breads, slows absorption of sugar from the bloodstream and can help prevent mood swings. Fiber-rich foods also keep you feeling full longer.

• Exercise. Like healthy foods, regular workouts boost the brain’s production of serotonin. Getting out in the sunlight is even better.