Women are more likely to gain weight after marriage, according to a recent study from Ohio State University.
One solution: Understand your nutritional needs. "Don't think you and your significant other can eat the same amount of food," says Jessica Levinson, a registered dietitian in New York City.
Don't match him bite for bite ... Men often are taller and more muscular than women and can eat more without gaining weight. While women generally need 1,600 to 2,200 calories a day -- the higher number is for younger, more active women -- the range for men is 2,200 to 2,800.
... or sip for sip. Women have lower amounts of an enzyme that breaks down alcohol and less body water to dilute it. Stick to one drink a day.
Don't gobble food. Men tend to eat faster than women. Put down utensils between bites, chew food thoroughly and use smaller forks and spoons (a teaspoon for cereal, say, rather than a soup spoon).
Know your needs. Talk to a registered dietitian or find an online calculator for calorie recommendations based on gender, age, size and exercise habits. Consider a multivitamin that offers sex-specific formulas; women often need more of certain substances (iron) and less of others (protein).
Eat well when you're alone. Fill up on fruits, vegetables, lean protein and whole grains.
Don't "let yourself go." Share diet and fitness goals with your significant other, ask for support and identify behaviors that interfere with them. Also find an exercise you can enjoy as a couple.
Be a creative cook. Tweak favorite "manly" foods: Bake chicken with bread crumbs rather than frying it, for example, grill with olive oil instead of butter and use low-fat cheeses in sandwiches and recipes.