How do large food portions affect weight?

Laura Motosko, MSEd, RD
Nutrition & Dietetics

The more food that is on your plate the more you are likely to eat it. Our stomach has a capacity to fill up with food beyond what we require sooner than our brain will register a feeling of fullness. Increased calorie consumption will cause weight gain.

Giant bottles of soda, extra-large bags of chips, and king-size candy bars are part of our everyday eating landscape. But bigger packages can sabotage portion control -- research has shown that people may tend to eat more food when it's served in larger containers.

To keep portions in perspective, there's a powerful tool in learning to visualize recommended serving sizes by relating them to common household objects. By comparing food portions to things you already recognize, you should be able to eyeball a food item and guesstimate how large it is. For example, your fist is about the same size as 1 cup of fruit or pasta; your thumb (tip to base) is the size of 1 ounce of meat or cheese; your palm (minus fingers) equals 3 ounces of meat, fish, or poultry; and your cupped hand equals 1 to 2 ounces of nuts or pretzels. Once you have serving sizes under control, you'll be ready to fit your favorite foods into your eating plan.

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Alexandria Hardy
Nutrition & Dietetics

The larger your portions are, the more calories you're consuming. For example, a typical breakfast may include a bowl of Honey Nut Cheerios with skim milk and a banana. All three of these options are healthy choices, but the portion size you eat determines how many calories you ingest. You could eat the recommended serving size of 3/4 C of cereal (110 calories), 4 ounces of milk (45 calories) and 1 small banana (90 calories) for a total of 245 calories for breakfast.

Larger portions of the same healthy foods can more than double the total number of calories, leading to potential weight gain if you are not burning/expending more calories than you are ingesting. For example, eating 2.25 C of cereal (330 calories), 8 ounces of milk (90 calories) and a large banana (120 calories) can add up to 540 calories. For many people, this second example is more realistic of intake as it is easy to serve yourself larger portion sizes if you don't measure out your food and beverages.

To avoid weight gain as a result of larger than appropriate portions, measure out your food according to the serving size listed on the Nutrition Facts panel. If you plan to consume more than one serving, adjust calories by multiplying by the number of servings you plan to eat.

Michaela Ballmann
Nutrition & Dietetics

When you sit down to eat a meal at a restaurant these days, it is more common than not to have a huge plate of food set in front of you.  This can lead you to eat more Calories than you normally would because you will naturally want to finish all the food on your plate.  Your body is also accustomed to a certain volume of food, so if you eat out a lot, your body is almost expecting to consume a large amount of food.  Buffets can also be problematic because there is a seemingly endless supply of food and no limit on the amount of servings you can have.  Where there is increased variety, Calorie intake increases because you will want to taste a little of everything, and then eat more of the things you really like, leading you to eat more than you would have if you only chose to eat two or three items.


I would recommend cooking more meals at home and buying smaller plates and glasses.  This really comes down to the psychology of food and the mind.  When you fill a small plate with food and finish it all, you feel much more satisfied mentally than if you had a large plate with the same amount of food, but only filling ½ or 2/3 of the plate.

Susan Mitchell, PhD
Nutrition & Dietetics

Large food portions = large intake of calories. This doesn't sound very sexy but the bottom line for weight gain and weight loss is the total number of calories eaten each day over time. If you look at portion sizes, they are extreme... cookies are the size of small pizzas and a typical serving could easily be shared among 2 or 3 people.

One very easy way to lose weight is to eat 1/3 deprivation or giving up items but rather cutting the portion size.

Dawn Marcus
Part of the reason Americans are getting bigger is because their food portions are expanding. For example, the United States Department of Agriculture recommends eating 5½ ounces of meat daily for the average adult eating a typical 2000 calorie per day diet; however, the largest hamburgers sold at popular fast-food chains are 8 to 12 ounces. One 12-ounce burger would be the recommended portion for two full days - not one meal! And burgers are just the tip of the iceberg. Researchers from the Department of Nutrition at the University of North Carolina evaluated average portion sizes for a wide variety of foods over two decades. Portion sizes increased for every food surveyed, except for pizza.
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Marisa Moore
Nutrition & Dietetics

When it comes down to it, weight management is all about calories in versus calories out. Large food portions can be a major diet derailer. Here's why...

  • Research shows that the more food we have in front of us - on a plate, at a buffet, in a cup or bowl - the more we tend to eat. So, start small. Use small plates, glasses and bowls to eat instead of larger vessels or even worse the entire bag of snacks.
  • Most people (even dietitians!) underestimate the number of calories in a plate of food. This portion distortion can lead to excess calorie intake.
  • Large portions of calorie laden drinks like juice, sweetened teas and coffee, smoothies and milkshakes can also lead to weight gain. Unlike solid foods, beverages don't tend to keep you feeling full very long. So rethink your drink. Limit caloric beverages to small portions and make the majority of your beverages calorie-free.
Alberta Scruggs
Nutrition & Dietetics

Eating food in portions greater than recommended serving sizes, increases kcalorie intake and may result in weight gain.

The United States Department of Agriculture (USDA) determines serving sizes based on the amount of kcalories and nutrients the food offers. Food manufacturers have the autonomy to determine the serving size of their food product and list it on the food label.

Serving sizes help you determine how many kcalories you are eating, no matter what you eat. For instance, 1/2 cup is the serving size of mashed potatoes (80 kcalories), 3 ounces of grilled chicken breast with the skin is 165 kcalories (without skin, it's 105 kcalories), and a pat or teaspoon of butter is a serving size (45 kcalories).

If you decide to increase the serving size of mashed potatoes to 1 1/2 cups, kcalories increase to 240. If you decide to increase the serving size of chicken breast with skin to nine ounces, kcalories increase to 495 (without skin, kcalories increase to 315). If you decide to increase the serving size of butter to 3 pats, kcalorie amounts increase to 135. No longer are the foods the recommended "serving sizes", they are "portion sizes" you created to eat.

Ruth Frechman
Nutrition & Dietetics

The saying, "Our eyes are bigger than our stomachs", is true for some people, especially if it's our favorite food. There is a tendency for many people to eat whatever is in front of them. This could be detrimental for losing weight. Some restaurants have plates big enough to feed two people. If you are trying to lose weight, eat on a salad plate. When you are done, you are done. You will probably eat enough calories to feel satisfied, not stuffed.

Kelly Shaughnessy
Nutrition & Dietetics

There are a couple ways in which large food portions can affect your weight. If you are eating large food portions at all of your meals, three or more times per day, you will gain weight. The reason you will gain weight is because large portions normally corresponds to large amounts of calories- and weight gain is caused by more calories eaten than calories burned.

Another way in which large food portions can lead to weight gain is by slowing your metabolism. If you only eat once or twice a day, having large portions, you may not be getting excess calories; however, you can actually slow down your metabolism by eating too few times throughout the day. A great tip that may help speed up your metabolism and thus lose weight is to eat smaller portions frequently throughout the day. Aim to eat a small breakfast to start the day, eat a small lunch and dinner, and have snacks in between- try not to go more than 2-4 hours without eating.

Deborah Beauvais
Nutrition & Dietetics

Gaining, losing and maintaining weight depends on the equilibrium of calories in vs. calories out. Calories in would be the food and beverages that you eat. Calories out would be the energy you expend in your daily routine along with the physical activities you participate in daily.

If your calories in are equal to your calories out weight should stay stable. But when the equation is changed and calories are higher than energy expenditures then weight will be gained. So eating larger portions than you need to equal out the calories you expend will result in weight gain. The reverse can also be true. Expending more energy than the calories you are eating will cause you to lose some weight.

Remember that various medications, age, and state of health also have an impact on this equation too. For further information it is best to consult with a Registered Dietitian to get the best weight maintenance scenario for your specific needs. can link you to a Registered Dietitian in your area.

Jessica Crandall
Nutrition & Dietetics

Large food portions can affect weight negatively by providing an excess of calories for the body at one time. Large food portions can also result in over-eating and a higher daily caloric intake than is necessary. Continued consumption of large food portions can eventually lead to adverse results, such as weight gain. 

Cassie Vanderwall
Nutrition & Dietetics
Many people say that we eat based on volume, not based on calories. If we choose large portions of high calories foods (fried foods/desserts/refined grains) we will be full at a great cost to our waistline. However, if we ate large portions, even the same size portion, of low calorie foods, such as vegetables this can help to fill us up and keep us full for longer on fewer calories.
Alexandra Lautenschlaeger
Nutrition & Dietetics

Large portions simply add more calories than what you need. Also, restaurants are increasing the portion size, while trying to keep their price down. There is a great website called portion distortion, which helps people realize that plates have gotten bigger. As we see bigger plates outside of the house, the more likely we see plates in the house. Hence, we start adding more calories. Also, calories out more than calories in help out greatly. Just remember though, it's a consistent balance. Don't exercise like crazy before a big meal, and then stop exercising. Portion control is the first and biggest step in weight management.

Molly Morgan
Nutrition & Dietetics
Large portions may or may not affect your weight.... the reason being is that the portions of food you eat should be based on your daily calorie needs. For example: a 150-pound person who is in active needs far fewer calories (and smaller portions) than a 150-pound person who exercises for 1 - 2 hours per day. Key tip: Adjust your portion sizes to what is right for you... it's not a one-size fits all approach. Work with a registered dietitian to create a custom plan for portions to meet your weight goals. Also utilize the tools with the USDA MyPlate program, check out this link:
Doreen Rodo
Nutrition & Dietetics

The larger your portion sizes, the more calories you will eat, thus you gain weight. You should only eat when you are hungry so don't stuff yourself with extra portions if you are already full. Eat slowly and then towards the end of the meal, rate your hunger. If you feel somewhat full, stop eating and save the rest for later. 

Remember to fill 1/4 of your plate with meat, 1/4 with starch and the other half with vegetables.

Jim White
Nutrition & Dietetics
Large portions of food affect your weight because they raise your blood sugar levels, which are an important factor in weight management. Large portions cause fluctuations in insulin production resulting in spikes in blood sugar levels thus disturbing hormonal balances. Weight gain is dependent on several factors but consuming large portions ignores the body's signal to stop eating and contributes to weight gain.
Judy Caplan
Nutrition & Dietetics
When you eat large portions you are more likely to store the extra calories as fat. Your body can only handle a certain amount of food at one time. Smaller more frequent meals and snacks help the body to metabolize food more efficiently. Smaller meals may also increase metabolism where huge portions may slow it down.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.