Meal frequency and portion size: What to know

It is widely accepted in modern culture that people should divide their daily diet into three large meals — breakfast, lunch, and dinner — for optimal health. This belief primarily stems from culture and early epidemiological studies.

In recent years, however, experts have begun to change their perspective, suggesting that eating smaller, more frequent meals may be best for preventing chronic disease and weight loss. As a result, more people are changing their eating patterns in favor of eating several small meals throughout the day.

Those who advocate for eating small, frequent meals suggest that this eating pattern can:

improve satiety, or feeling full after a meal
increase metabolism and body composition
prevent dips in energy
stabilize blood sugar
prevent overeating.

While a few studies support these recommendations, others show no significant benefit. In fact, some research suggests it may be more beneficial to stick with three larger meals.

Here is what the research says.

Early epidemiological studies suggest that increased meal frequency can improve blood lipid (fats) levels and reduce the risk of heart disease. As a result, many experts advise against eating fewer, larger meals a day.

Over the years, some studies have supported these findings, suggesting that people who report eating small, frequent meals have better cholesterol levels than those who consume fewer than three meals per day.

In particular, one 2019 cross-sectional study that compared eating fewer than three meals per day or more than four meals per day found that consuming more than four meals increases HDL (high-density lipoprotein) cholesterol and lowers fasting triglycerides more effectively. Higher levels of HDL are associated with a reduced risk of heart disease.

This study observed no differences in total cholesterol or LDL (low-density lipoprotein) cholesterol. It is important to note, however, that this is an observational study, meaning it can only prove association, not causation.

Additionally, one review published in the American Heart Association’s journal Circulation concluded that greater eating frequency is associated with a reduced risk for diabetes and cardiovascular disease, according to epidemiological studies.

There is a commonly held notion that more frequent meals can help influence weight loss. However, the research on this remains mixed.

For example, one study compared eating three meals per day or six smaller, more frequent meals on body fat and perceived hunger. Both groups received adequate calories to maintain their current body weight using the same macronutrient distribution: 30% of energy from fat, 55% carbohydrate, and 15% protein.

At the end of the study, researchers observed no difference in energy expenditure and body fat loss between the two groups. Interestingly, those who consumed six smaller meals throughout the day had increased hunger levels and desire to eat compared to those who ate three larger meals per day.

Although calorie intake was controlled in both groups, researchers hypothesized that those who consumed frequent meals would be more likely to consume more daily calories than those who ate less frequently.

Results of another large observational study suggest that healthy adults may prevent long-term weight gain by:

eating less frequently
eating breakfast and lunch 5 to 6 hours apart
avoiding snacking
consuming the largest meal in the morning
fasting for 18-19 hours overnight.

Moreover, according to the United States Department of Agriculture (USDA) Scientific Report of the 2020 Dietary Guidelines Advisory Committee, due to inconsistencies and limitations in the current body of evidence, there is insufficient evidence to determine the relationship between meal frequency and body composition and the risk of overweight and obesity.

Does eating frequent meals boost metabolism?

Small, frequent meals are often touted as a cure-all for obesity. Many believe that eating every 2 to 3 hours can help boost metabolism.

Digestion of food does require energy. This is known as the thermic effect of food (TEF). However, it does not appear that meal frequency plays a role in boosting metabolism.

In fact, some studies suggest fewer, larger meals may increase TEF more than eating frequent meals.

Although evidence to support increased meal frequency in the general population remains mixed, several experts believe that eating small, frequent meals can benefit athletes.

According to the International Society of Sports Nutrition, athletes who follow a reduced-calorie diet may benefit from eating small frequent meals with adequate protein because it can help preserve lean muscle mass.

When prioritizing total daily calorie intake, limited evidence suggests that, in athletes, a higher meal frequency may increase performance, support fat loss, and improve body composition.

People who eat more frequently are more likely to have better diet quality. Specifically, those who consume at least three meals per day are more likely to have a greater intake of vegetables, greens, legumes, fruit, whole grains, and dairy.

These individuals are also more likely to consume less sodium and added sugars than those who consume two meals per day.

Similarly, another 2020 study published in the British Journal of Nutrition found that increased meal frequency — approximately three meals per day — is associated with higher diet quality.

Researchers found that snack frequency and diet quality varied depending on the definition of snacks.

Based on the presented studies, no substantial evidence supports one eating pattern over the other. Yet many of these studies also have limitations.

For example, there is no universally accepted definition of what a meal or snack consists of. This can have an impact on study outcomes.

With that said, both eating patterns can be beneficial as long the primary focus is on healthful eating habits.

Who should consume small, frequent meals?

A review published in Nutrition in Clinical Practiceshows that certain populations may benefit from six to 10 small, frequent meals. These include people who:

experience early satiety
are trying to gain weight
have gastroparesis
have gastrointestinal symptoms such as nausea, vomiting, or bloating.

If your goal is to lose weight, it is important to be mindful of your portion sizes. Be sure to stay within your allotted daily calorie needs and divide them among the number of meals you consume.

For example, if you need 1,800 calories to maintain your weight and choose to eat six small meals daily, each meal should be around 300 calories.

Small, frequent meals often come in the form of ultra-processed foods and snacks that fall short in many vital nutrients your body needs. Thus, it is essential to focus on the quality of the foods you consume.

Who should consume fewer, larger meals?

People who may benefit from three larger meals per day include:

those who have difficulty practicing portion control
those who tend not to eat mindfully
people who live busy lives and may not have time to plan and prepare several nutritious mini-meals a day.

Again, keeping diet quality in mind and prioritizing whole foods is essential. Fewer meals mean fewer opportunities to get in key nutrients the body needs.

While we do not have strong evidence to support the importance of meal frequency, substantial evidence supports the overall health benefits of following a well-balanced, nutrient-rich diet.

According to the Dietary Guidelines for Americans 2020–2025, a healthy diet should:

emphasize fruits, vegetables, whole grains, and low-fat or fat-free milk or dairy products
include protein from various sources, including seafood, lean meat and poultry, eggs, nuts, seeds, soy products, and legumes
stay within your allotted calorie needs
limit added sugars, cholesterol, trans fats, and saturated fats.

Evidence is mixed about the importance of food frequency. While there is no solid evidence to suggest that one eating style is superior to the other, both can offer health and wellness benefits if you follow a healthy eating pattern.

Thus, it ultimately comes down to personal preference and which approach works best for you. Additionally, if you have certain health conditions, one style may benefit you over the other.

As always, consult your healthcare provider before making any significant changes to your diet.