It's happening — it's getting dark earlier, and our kids are going back to school. ... Fall is about to begin. And get this, according to John de Castro, a professor of psychology at Sam Houston State University in Texas, we eat about 200 calories more per day in the fall, and not because of Thanksgiving — this is in addition to that weight gain.

The likely reason we do this is in preparation for the winter months of famine. What famine, you say? These days there is none — probably another reason we keep gaining weight as a country. But in the past, we ate when foods were plentiful — like the time of the fall harvest.

Perhaps we also eat more because swimsuit season has ended, and we can start wearing more clothes. Whatever the reason, here are a few tips to keep you healthy and living well during the fall months.

Make soup: Healthy vegetable-based soups are great (see: www.DietDetective.com for a chicken soup recipe). Make sure to avoid high-fat soups loaded with fatty meats, cream and/or cheese. Not only do they pack on the calories, but recent research from the University of Cambridge in the United Kingdom indicates a high-fat diet can make you "fat and lazy."

Watch what you eat: Avoid unconscious eating while watching football and the new fall TV lineup. Never bring the whole bag or bowl of anything to the couch or coffee table — premeasure it in the kitchen beforehand. When it comes to chips, make sure they're baked, not fried. For pizza, watch the toppings — they can double the calories.

Eat apples, pears, sweet potatoes and butternut squash: Apples have been shown to reduce the risk of some cancers, as well as cardiovascular disease, asthma and diabetes, and they help keep blood vessels healthy and reduce inflammation, a benefit also found in vitamin A-rich butternut squash and sweet potatoes. A medium pear has 5.5 grams of fiber, 212 milligrams of potassium and is a good source of vitamin C.

Pack a healthy lunch: While there are signs that the recession is ending, it doesn't hurt to pack your own lunch. Avoid processed foods with added sugar, fatty lunch meats and high-calorie beverages, including juices. (See more brown-bagging tips at www.dietdetective.com/column/brown-baggin'-it.aspx.) But be careful about restricting your children's junk food intake too much, says a recent study reported in the Journal of Pediatrics. A combination of "high parental restriction and low self-control" puts kids at the highest risk for weight gain. The best advice is to teach your kids to control their own behavior and set a good example.

Enjoy the season: Go to museums, go hiking, take long walks and bike rides, and use a pedometer. Keep in mind that it gets darker earlier, so there are fewer outdoor options for physical activity in the evening. Make adjustments by joining a gym, planning evening walks at the mall or becoming an early riser. Walk your kids to school. Make it interesting by using www.mapmywalk.com or www.maps.google.com, which has a drop-down menu where you can choose "walk" to directions and the distance to anywhere.

Relax and stay calm: Try to readjust to the fall work or school schedule to avoid eating due to stress from mounting "back to school/back to work" pressures. You don't have to avoid eating altogether, but you do need to make healthier choices. Try to keep junk food out of your office and home, and make sure to have plenty of fall apples and pears on hand. If that's all you have, that's what you'll eat. Also, consider air-popped popcorn. In a first-of-its kind study, scientists at the American Chemical Society reported that snack foods like popcorn contain "surprisingly large" amounts of healthful antioxidant substances called polyphenols.