Editor's note: This is the first of two parts on situations that can affect diet. Part 2 features life changes (such as moving, new job, loss and injury).

Sometimes, just trying to keep things together when you're stressed is difficult enough. That's when worrying about your diet can seem unimportant. However, with a few simple, conscious moves, you can avoid those diet-busting situations that come along with certain life stages. Below are a few tips on how to navigate safely past them.

GETTING MARRIED

Research shows that there is an average weight gain of 6 to 8 pounds over a two-year period after tying the knot. Marriage means more frequent meals — and lots of dining out — which means higher calories. But even when cooking, married people tend to prepare larger amounts of food than singles, so portion sizes increase. And they pay less attention to what they're eating because they're dining with another person. Also, there is a lot of sitting around watching TV and snacking on high-cal foods.

Additionally, people tend to take on the habits of their spouses. And lastly, we tend to let our guards down after getting married, so we're more likely to miss a morning at the gym now and then.

The fix: Mentally prepare for eating out. It's not always easy to eat healthy while dining in a restaurant, so pick places where you can order healthful dishes.

D. Milton Stokes, of the American Dietetic Association, encourages his patients to order appetizers as their entrees or to start the meal with a tomato-based soup or field green salad and then share an entree.

If your partner has unhealthy eating habits, maintain your eating and exercise independence and try to set a positive example (no nagging, though).

Keep in mind, your partner may have a faster metabolism or more active lifestyle than you. He or she might be able eat a pint of ice cream and not gain weight. Have alternative low-cal foods in the house so you can eat something when he or she indulges. Also, have a talk with your new spouse to set limits on bringing home foods you can't resist.

Remember that being physically fit helps keep your marriage healthy because you feel better about yourself and your partnership.

HAVING CHILDREN

Parenting can seem overwhelming and eating healthfully sometimes feels impossible. Plus, new moms frequently struggle with losing the pounds they gained during pregnancy, and many fathers eat right along with their spouses. Even parents who exercised regularly before having a baby typically don't anticipate the difficulty of weaving activity into their new, hectic schedules.

The fix: Instead of takeout and fast food, try preparing healthful foods over the weekend and freezing them to reheat later in the week. Also, keep a supply of quick and easy low-calorie frozen dinners (Healthy Choice, Lean Cuisine, Smart Ones, Kashi) on hand for when there's just no time to cook. Look for ones with lower sodium content. Take the baby out for long walks in a stroller or try a parent-and-child activity class at a fitness center. Also, you might want to invest in a Netflix membership (http://netflix.com) and check out various exercise DVDs.

DIVORCE

Divorce creates stress; however, there is one silver lining: Researchers reporting in the journal Obesity Research found that people tend to lose weight after divorce. Experts are hesitant to speculate why, but research has shown that dining alone leads to smaller portions and decreased consumption overall. Plus, the "back on the market" syndrome may be at work — that is, eating healthier foods, working out and dressing differently to create a better appearance.

The fix: "If you're eating less and maintaining your weight, there's probably no real concern," says Stokes. Try increasing your physical activity. Increased exercise has been shown to help make you feel better.

RETIREMENT

Many retirees spend lots of time on golf courses and tennis courts; however, most of their time is spent eating out and relaxing. There are cruise ships with buffets, clubhouses and card games. Life centers on food. And, as we get older it becomes more difficult to do everyday things, which is why physical activity, including strength training, is critical. Also, we lose lean muscle tissue, which means our metabolism slows down and we burn fewer calories.

The fix: Metabolism slows with aging, so pick healthful meals ahead of time; it's easy to lose focus when dining out socially.

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.