Summer time is a great time to add a little science to your meal


The sun is out, the temperature is climbing, and coats and sweaters are put away for the season. Beaches and pools are very inviting, which means now those winter pounds are harder and harder to ignore

And we have just the information you need to help get you started.

Science helps us understand why we eat when we eat as well as how much – and just what you can do to be more aware of signals that can be subtle but so very powerful, tempting us away from those better choices.

The Environment

It is a known fact that we eat more when the temperature is cold than when hot – particularly when the temperature stays cold for a longer period of time. This makes sense for survival, as the body’s core temperature requires more energy to self-regulate – energy we get from more consumed food. So summer with its higher temperatures can indeed decrease our calorie intake – unless we crank up the air-conditioner. You might consider keeping your eating area a bit warmer to decrease that drive to eat more.

Lighting can also give a subtle stimulus to eating behavior. Dimmed or soft lighting has been linked to more calorie ingestion. In contrast, very bright light works the opposite, particularly in restaurants. People tend to be more comfortable in lower light and thus stay at the table longer, order a dessert when they otherwise might not, or order another cocktail, leading to more calories. Because people are less inhibited and less selfconscious when the lights are low, they are also likely to eat more than planned. This seems to be even more likely if you are dining out with others. And the more people you are eating with, the more you are likely to eat yourself! So choose an eating area that is more brightly lit – you will eat less. And watch the number of your eating companions – as the number of people in your party grows, so does your food intake!

The aroma of food is something most people enjoy... that of fresh baked bread or just-out-of-the-oven cookies remind us of family, friends and special occasions. It’s a powerful stimulus. However, aromas can influence food consumption through taste enhancement or suppression.

For example, unpleasant odors have been shown to shorten the duration of a person’s meal and to decrease the amount of food eaten. Yet the reverse is not necessarily true: it’s not clear whether favorable odors increase food ingestion. Research shows that whether you taste a food or smell it, sensory-specific fullness takes place in a very short time frame. This means that aromas might be more likely to have an immediate effect on food ingestion, whether you take your time to start eating or dive in right away – except for unpleasant odors that make you pass on the food altogether. Consider that when you think of whether to add garlic to your meal or whether fresh sauerkraut should be added to that Reuben sandwich.

Have you ever wondered why restaurants make it a point to play background music? Here’s your answer: soft music has an effect on food ingestion. Typically, it will make you slow down your eating, which results in a longer meal duration, resulting in a higher intake of both food and drinks. And when preferred or favorite music is heard, individuals feel more comfortable, stay even longer, and are more likely to order a dessert or another drink. When the music is loud, fast, or very grating, people tend to spend lesstime in a restaurant. But this can have a contrasting effect as well: some studies have shown that to leave an environment that has loud and unpleasant music, you might even overeat as you quickly ingest your food. So think twice about whether you want to listen to music at all while you eat!


Convenience is something we all appreciate, but unfortunately it can work against us when it comes to what and how much we eat. Convenience is one of the strongest influences affecting the amount of food eaten. Cafeteria studies show that people ate more ice cream when the lid of an ice cream cooler was left open than when it was closed, they drank more milk when the milk dispenser was placed close to the dining area, and they drank more water when a water pitcher was on their table than when it was farther away. Other studies show that we are much more likely to eat almonds if they were shelled versus unshelled and more likely to use silverware than chopsticks (which require more of an effort) in Chinese restaurants. When given Hershey’s Kisses on their desks as compared to two yards away from their desk, secretaries ate 5.6 more chocolates a day than when they had to stand up and walk to get them.

Packaging makes a big difference as well. Lab studies suggest that we tend to eat less when offered food in multiple small packages than when offered a large package of the same volume. Researchers believe that part of the reason may be that the smaller packages provide stopping points to reconsider whether you will or should eat more, rather than finishing off an already opened larger bag of food. Look for smaller packages of the foods you are planning to eat. Put the higher calorie foods on the highest or lowest cupboard level, and stick the ice cream in the very back of your freezer.


Visual cues can be subtle or not so subtle. Simply seeing a food can stimulate you to eat when you weren’t even aware of wanting to eat. As an example, when secretaries had 30 Hershey’s Kisses placed openly on their desks as compared to opaque jars, the candies were eaten 46 percent more quickly. When individuals were given a choice of sandwich quarters wrapped in transparent wrap versus opaque wrap, more sandwiches in the clear wrap were eaten at any one sitting.

Variety stimulates us also, although very subtly. Research has shown that if you are offered an assortment of yogurts with three different flavors, you are likely to consume an average of 23 percent more yogurt with the different flavors than if offered only one flavor. Increasing the variety of a food can increase the amount of food consumed, a finding that affects all ages and both genders. For example, when people were given a batch of 300 M&M candies, one group getting the candies in seven, the other in 10 different colors. Although the taste of each color was identical, those who had been given a bowl with 10 colors ate 43 percent more (91 versus 64 candies) over an hour than those who had been given seven colors.

Drinking from a tall glass as compared to a shorter, wider glass results in less volume intake. Even if the vertical dimension is identical to that of the horizontal dimension, people still tend to overestimate height by 20 percent. It has been shown that this visual perception can cause you to pour and drink 88 percent more juice or soda into short, wide glasses than into tall, narrow glasses that hold the same volume. You think you are drinking more when your glass is tall. And eating from a smaller plate as compared to a larger plate makes you think more food has been eaten, even if the amount is exactly the same. Consider taller glasses, smaller plates, similar if not same-colored themed meals and use science to help you make the right choices.

Dr. Dace Trence is Director of the Diabetes Care Center and Professor of Medicine at the University of Washington Medical Center in Seattle. She is also the University of Washington Endocrine Fellowship Program Director and Director of Endocrine Days, a medical education program for endocrinologists practicing in the Pacific Northwest. She is on the American College of Endocrinology Board of Trustees and chairs the CME Committee and is also chair of the AACE Publications Committee.