Does Exposure to Bigger Portion Sizes Lead to Weight Gain?

Research study measures whether adults repeatedly served larger portion sizes at lunch gained weight over 6 months time.

One promising area of study in obesity research is portion control. The convenience of accessible, high calorie food makes it easy to overeat and gain weight. As standard meals have increased in size over the years, so have our waistlines.

The problem is, sometimes we aren’t even aware that our portions are getting bigger! Especially, when food is prepared for us at work or when we eat out. A quick look at the lunches in the photos show that the difference between the 1600 calorie lunch and the 400 calorie lunch don’t actually look that different. My teenager told me he couldn’t be fooled! Even if he was served a plate with higher calories, he wouldn’t eat more food if he wasn’t hungry for it. But research disagrees.

Portion size effects of different lunches on weight gain. Research review

A study published in 2014 was designed to look at the impact of simply being exposed to a high calorie lunch. The researchers wanted to find out if adults adjusted their calories the rest of the day when they ate more calories at lunch, and if just by being exposed to more calories made them eat more food at lunch and gain weight.

The Study Design: Effects of Portion Sizes

250 working adults at a large medical complex were offered free box lunch during the work week for 6 months. The participants were put into three different calorie groups. One group got a lunch that contained 1600 calories, one group received a similar lunch that was 800 calories, and a third group received a similar lunch, with 400 calories. There was a fourth group that had no intervention as a control group. This image is a sample of what the participants got:

Although all the lunches were very similar, portion sizes changed to create the right amount of calories to be studied. There was a rotation of 15 different lunches, and I created 2 of them to share. I had fun recreating these lunches to really see for myself how subtle the difference can be, and how easy it is to eat more food than we need!

The Sandwich Lunch box in 3 different portions
3 different chicken wrap portion sizes for lunch
Lunch 1: 1600 calories
  • 12 Inch tortilla
  • 28 grams lettuce
  • 4 ounces chicken
  • 2 ounces lite Caesar dressing
  • 0.5 ounces croutons
  • 4 tablespoons Parmesan cheese
  • 28 grams tomatoes
  • 1 cup grapes
  • 4.5 ounce brownie
  • bottled water
Lunch 2: 800 calories
  • 10 Inch tortilla
  • 28 grams lettuce
  • 3 ounces chicken
  • 1 ounces lite Caesar dressing
  • 0.5 ounces croutons
  • 3 tablespoons Parmesan cheese
  • 28 grams tomatoes
  • 1 cup grapes
  • 1 ounce brownie
  • bottled water
Lunch 3: 400 calories
  • 8 Inch tortilla
  • 28 grams lettuce
  • 1.5 ounces chicken
  • 1 ounces lite Caesar dressing
  • 0.5 ounces croutons
  • 1 tablespoons Parmesan cheese
  • 28 grams tomatoes
  • 0.5 cup grapes
  • bottled water
The salad lunch box in 3 different portions
three different portion sizes for lunch caesar salads
Salad lunch 1: 1600 calories
  • 6 ounces Romaine Lettuce
  • 4 ounces lite Caesar dressing
  • 4 ounces chicken breast
  • 2 ounces Parmesan cheese
  • 1.5 ounces croutons
  • 1 dinner roll
  • 1 pat of butter
  • 1 cup strawberries
  • 141 grams Chocolate chip cookie
  • bottled water
Salad Lunch 2: 800 calories
  • 5 ounces Romaine Lettuce
  • 3 ounces lite Caesar dressing
  • 3 ounces chicken breast
  • 1.5 ounces Parmesan cheese
  • 1 ounces croutons
  • 1 dinner roll
  • 1 pat of butter
  • 1 cup strawberries
  • bottled water
Salad Lunch 3: 400 calories
  • 4 ounces Romaine Lettuce
  • 2 ounces lite Caesar dressing
  • 1.5 ounces chicken breast
  • 0.5 ounces Parmesan cheese
  • 0.5 ounces croutons
  • 1 dinner roll
  • 1 cup strawberries
  • bottled water

After 6 months of consistently being offered the lunches, weight was measured to see if there was a weight gain.

The Results of Portion Controlled Lunches

The participants who were repeatedly offered the 1600 calorie lunch gained the most weight (almost 2 lb). The adults who were served the 400 and 800 calorie lunch maintained their weight, and some lost weight. What’s more interesting, the control group with unregulated calories gained weight! This could be an important finding, considering, when in a natural work environment, it’s more likely for us to overeat, than if our calories were controlled.

Other studies have shown portion controlled meals minimize weight gain and even enhance weight loss.

Final Thoughts:

While we might think it’s unnecessary to monitor portion sizes, it is unlikely to support weight loss. It’s much too easy in our food culture to be oblivious to small changes on our lunch plate, but the difference in calories might be very significant.

References:

READ NEXT==> THE ULTIMATE GUIDE TO PORTION CONTROLP