Twenty years ago, a small popcorn at a movie theater had just 270 calories; today, it has 650 calories. And a tub of popcorn these days can top 1,600 calories. Of course, you can practice portion control—you don’t have to eat the whole bucket. But if it's there, there’s a good chance you’ll scarf down a good amount of it.

Faced with an abundance of food, we have a hard time saying no, according to a 2015 review of 72 studies published by the Cochrane Library. “Research consistently shows that when we’re presented with a big portion, we eat more—even when we are not hungry,” says Lisa Young, Ph.D., R.D., author of “The Portion Teller Plan” (Morgan Road Books, 2005) and an adjunct professor of nutrition at New York University.

So can shrinking our waistlines be as simple as practicing portion control? That can help, Young and other experts say. But downsizing portions is only one piece of the puzzle. For weight control—and good health—there are foods you’ll actually want to eat more of. And unless you take steps to ensure that you feel full on smaller portions, your serving sizes will probably creep up again. Follow the techniques below to help you train your brain to recognize and stick with healthy helpings of food.

Smart Size Your Meals

Using portion control as your primary healthy-eating strategy allows you to eat almost any food while keeping calories in check. And the calorie savings are significant: Normalizing portions could reduce calorie intake by almost one-third—about 527 calories per day, according to one study. If all else remains equal, you could lose a pound per week.

Scoop and pour. Pull out some measuring spoons and cups to dole out precise portions of your favorite foods for a few weeks. You might be surprised to see that a serving of the cereal you eat most days is ¾ cup, while filling up the bowl to what looks like a reasonable portion puts you closer to 2 or 3 cups. (For a guide to serving sizes, go to

Share with a friend. When dining out, start with your own healthy appetizer, such as salad or soup, and split the entrée. It’s also wise to go halfsies on extras, like a side of french fries or dessert. The first few bites often taste the best, anyway, according to Jean Kristeller, Ph.D., author of “The Joy of Half a Cookie” (TarcherPerigree, 2015) and professor emeritus of psychology at Indiana State University. That’s because satisfaction with a food declines with continued consumption of it, a concept known as taste satiety. We’re likely to eat more if the portion is large, whether or not the food tastes fabulous. Instead, try having a smaller serving, and slow down so that you can enjoy each bite.

Watch your portions of healthy foods, too. Plenty of nutritious foods, such as almonds and dates, are also high in calories. And when people think that a food is good for them, they underestimate calories, according to a study from Cornell University. The researchers found that diners who ate in a restaurant they thought of as healthy believed they were taking in 151 fewer calories than the meal actually had. 

Stay Satisfied

Resized portions will seem small only if they’re not satisfying. By favoring satiating foods, you can feel full from smaller servings.

Focus on fiber. Simply choosing foods that are rich in fiber can help fill you up. (Think of how you feel after 1 cup of oatmeal vs. the same size serving of cornflakes.) In one study, increasing fiber intake to at least 30 grams per day for 12 months helped 240 adults who were at risk for type 2 diabetes lose almost as much weight as people who followed a more complicated diet that specified exactly how many servings of carbs, vegetables, and protein to consume. They also lowered their blood pressure, and improved insulin resistance and fasting blood insulin levels. Fiber-rich choices include beans, fruits, vegetables, and whole grains.

Curb your appetite. Take the edge off your hunger with a healthy appetizer; that will help you limit yourself to that 1-cup serving of cooked pasta. A salad before or during the meal helped people eat 11 percent fewer calories overall, in a study in the journal Appetite. In another study, starting a meal with soup can cut calorie intake by up to 20 percent. But stick to a lower-calorie broth-based soup like minestrone or chicken (and check sodium, too, because soups often contain lots of it).

Take smaller bites. That can help you keep portions in check. For example, research from the Netherlands found that people who took tinier sips of tomato soup ate about 30 percent less than those who gulped it. (The researchers said that the finding applies to solid food, too.) 

Think Big—Sometimes

There are a few instances when oversized portions may be helpful—if you’re careful.

Supersize the salad. It’s difficult to find fault with a heaping bowl of raw vegetables. So in addition to the standard lettuce, tomato, and cucumbers, add asparagus, beets, green beans, or whatever vegetables you like. Watch out for the extras, though—cheese, croutons, wonton noodles, and, of course, dressing can catapult a salad’s calorie count into double cheeseburger range. At a salad bar? Measure out the extras. If you’re at a restaurant, get the dressing on the side so that you can control how much you put on, Young says. Or just ask for balsamic vinegar plus a little olive oil splashed on top.

Eat veggies family-style. Measure out carbs (like potatoes) and protein (like steak) to control portions of higher-calorie foods. But put vegetable side dishes on the table so that people can help themselves to abundant servings of those filling, low-calorie foods. Cornell University researchers found that people eat more of foods that are right in front of them. In the case of fiber-rich, low-calorie produce, you might fill up on fewer calories.

Increase portions with produce. Not sure a half-cup serving of cooked rice will fill you up? Round it out with vegetables. For example, add 1 cup of chopped fresh spinach per serving of rice for a bulked-up but not weighed down side dish. (Mix the spinach into the hot rice as it finishes cooking, stir, and cover the pot for 1 minute. After the heat wilts the greens, stir again before serving.) You get a bigger portion—and an extra serving of nutrient-packed veggies.

Editor's note: This article also appeared in the March 2016 issue of Consumer Reports on Health.