The portions on our plate are larger than ever, which is bad news for those of us who want to shed some pounds. But not all hope is lost - understanding our relationship with how much you eat is the first step to gaining back control.

Maintaining a healthy weight throughout our lives can help prevent chronic diseases such as heart disease, diabetes, certain cancers, and several other conditions.  The formula for losing excess weight is pretty straightforward: burn more calories than you take in.

Sounds simple, but given the fact that the portions we eat are larger than ever these days, keeping our calories in check can often feel like a constant uphill battle.

What exactly is a portion, and how are portions different from servings?

A portion is simply how much food you are eating in one sitting, and is something you yourself can control. Whether you are dining out, enjoying a meal you have cooked, or snacking on packaged food you brought home from the grocery store, you can decide how much to eat at any one time.

A serving, on the other hand, is the amount of food specifically listed on its package’s nutritional label that the manufacturer standardizes to make it easier to compare similar foods. The serving size reflects the amount that people typically eat or drink. For example, even though a bag of sliced bread contains many slices of bread, only one of those slices is considered a serving. Likewise, one serving of cheese is actually 2 oz, which is only about twice the size of your thumb.

Larger portions not only raise your number of calories each day, they also suppress your ability to assess how much you are eating.

So can simply reducing your portion sizes - in other words, intentionally measuring and managing how much you eat - translate to real weight loss?  Let’s read on to find out.

How portions have become supersized

Over the last two decades, restaurants and food manufacturers have offered larger and larger portions, in many instances doubling or even tripling the size of what used to be considered normal.

For instance, a bagel from 20 years ago would have a 3-inch diameter, whereas it is common to find a 6-inch wide bagel today. A typical cheeseburger used to weigh 4.5 oz, where today’s cheeseburger can easily weigh in at 8 oz, and a regular-sized soda from back then was 6.5 oz, whereas today 20 oz is considered a normal size to drink.  

Understanding the “Portion Size Effect”

It would seem to make sense that the more you eat, the greater the number of calories you consume, and it turns out that the portions at your table are pretty influential in determining how many extra calories you get.

Research completed by Roig et al., (2020) has actually confirmed that when you eat, a Portion Size Effect occurs, explaining that when large portions of food are offered, more is eaten and more overall calories are consumed. A study conducted by Hetherington et al., (2018) also  confirmed that this effect appears to be universal, affecting both children and adults across different meal and snack types like packaged foods, handheld foods like sandwiches, beverages, and even fruits and vegetables. It is also seen in multiple environments such as in restaurants, the office, and in the home.

Inherent biases affect how you judge portion sizes

As a general rule,  people are not very skilled at judging how much they are eating at any given time, and more often than not, they will underestimate the caloric content of the foods on their plate (Hetherington et al., 2018).

In addition, when it comes to assessing the quantity of food, people are more apt to underrate the amount as sizes increase, and more easily notice when their food quantity downsizes. This especially rings true for foods that take on the shape of their containers, like pasta and rice.

Unfortunately, the feeling of fullness is often pushed aside in favor of other cues that keep you eating more, like the attractiveness or easy access of food or the festive eating environment you are in  (Hetherington et al., 2018).

How the way you eat makes a difference in how much you eat

As humans, people share a number of eating behaviors that make them more prone to consuming excess food (Roig et al., 2019).

For starters, many people eat at a fast pace, and faster eating is shown to be associated with larger bites that are chewed less. Food that is chewed less spends less time in your mouth, which decreases your sense of satiety by dampening the signal you need to let you know you are full.

People also often strive to finish everything on a plate during a meal, a tendency called "plate cleaning" which is associated with increased body weight and obesity. In many cases, this habit is established during childhood when parents expect their children to clean their plates to avoid waste.

Eating mindlessly is another common behavior that is linked to excessive calorie intake. If you think about it, most people eat without thinking all the time. You may find yourself shoveling food down while watching TV, reading, working, and scrolling on the phone, often eating straight out of the chip bag without a sense of how much you are actually consuming. And you may do this whether you are still hungry or not.

When you eat while distracted, not only do you pay less attention to how much you are consuming, you are also less likely to recall how much you ate during previous meals, impairing your ability to make smart decisions at the table.

5 practical ways to eat less

If you want to start eating less to slim down, paying attention to your portions is a great first step to reducing your overall calories, and there are several ways to do so.

Remember that if you want weight loss that lasts, sticking to reasonable portions should be an integral part of your healthy eating lifestyle.

Learn your portions. Familiarize yourself with what makes a portion on your plate. Many handy infographics exist online that make it easier to get a pretty good idea of how much you’re actually eating at each meal. For example, your own hand can be a powerful tool in your portion-control learning, with your palm signifying a 3 oz. serving of meat, your fist can represent a full cup, and your thumb can indicate a 1 oz. serving of cheese.

When eating out, split the main meal with a friend or family member or ask for a to-go box right away for half your meal to take home and enjoy the next day.

When eating at home, put any extra food away and out of reach after serving to resist the temptation of taking seconds and thirds, and serve the food on individual plates rather than large family-style dishes for all to grab from.

When eating while watching TV, never eat straight out of the package or bag. Eating while distracted is a surefire way to rack up the calories quickly. Always put a specified amount onto a plate or bowl and then put the package away.

Between meals, go ahead and eat a healthy fruit, vegetable, or whole-grain snack if you are hungry. Healthy fat foods like a handful of walnuts, avocado, and salmon and lean protein sources such as white chicken, turkey, and eggs also make nutritious snacks while keeping you satiated before your next meal. Reaching the lunch or dinner table with a semi-full stomach makes it much easier to keep from overeating.