Snacking under scrutiny: Is it bad to eat between meals?

Nowadays, time is one of our most precious commodities. The hectic pace of life often requires strict organization, both at work and at home.

Within this routine, eating also requires a certain amount of structure, from making the shopping list to planning the meals you'll eat throughout the week, which is known as batch cooking. However, there are relatively common occasions when food consumption arises in an unorganized manner, what we traditionally call "snacking." This behavior involves eating food outside of main meals, motivated by hunger , habit, or a simple craving.

Now , is this practice beneficial or harmful to health? Everything seems to indicate that it depends as much on the context as on the foods eaten.

Traditionally, we have accepted that eating three to five meals a day is associated with a healthier diet, especially during growth stages and in healthy adults. This distribution includes three main meals a day and two optional smaller meals, which could include snacks.

However, there are studies that support eating only three main meals to achieve the greatest benefits. The authors of a study published in The Journal of Nutrition in 2017 stated that frequent snacking outside of main meals increases the risk of a higher body mass index (BMI) and obesity.

Other authors indicate that eating three meals a day instead of four is associated with an increase in HDL cholesterol (good cholesterol), while others argue that eating fewer but larger meals increases thermogenesis, the energy the body expends in the process of digesting and metabolizing nutrients . In this sense, snacking does not seem to be a healthy option.

The impact of including additional meals (snacking) on ​​BMI, cholesterol levels, and thermogenesis is not the only area of ​​study. Other lines of research have analyzed how snacking might influence insulin secretion and glycemic control, although there is no clear consensus regarding a generalized effect.

Some authors suggest that eating fewer meals per day or skipping main meals can increase the risk of insulin resistance. However, others suggest that insulin sensitivity and glycemic control are more effective when eating only two meals a day, rather than snacking, which can lead to up to six meals a day.

These two opposing results prevent definitive conclusions about snacking and glycemic control. Therefore, we should not focus solely on the act of snacking itself, but rather on the composition of the foods that make up this unorganized intake, which can be beneficial in some situations such as weight loss or exercise.

When a person tries to lose weight, one of the goals of their diet is to create a calorie deficit. At first, one might think that snacking makes it harder to reduce energy intake. But meal frequency could be a useful tool for controlling appetite and diet adherence.

Ghrelin, also known as the hunger hormone, influences appetite, encouraging food intake. It appears that eating more meals a day helps reduce ghrelin spikes, improving appetite and preventing overly hungry arrival at the next meal.

However, in practice, the effect of snacking on hunger cannot be reduced to this physiological effect . For example, eating six smaller meals a day caused greater feelings of hunger than eating three larger meals in American volunteers. The same results were obtained in another study that analyzed food consumption only at breakfast and lunch.

A large cohort study found that adults who ate less frequently (only two meals a day) and avoided snacking tended to gain less weight over the years compared to those who ate more frequently. Therefore, it seems that snacking may cause a person to feel less satisfied, having the opposite effect on appetite control, hindering the weight loss process.

So, should snacking be banned in these cases? No. What we should do is pay attention to the composition of the snack , since eating foods rich in protein, fiber, or whole grains, such as nuts, yogurt, or fruit, can increase feelings of satisfaction and help control appetite.

This could reduce overeating during main meals and contribute to weight control in people who are overweight or obese. However, frequently consuming energy-dense snacks can lead to weight gain.

The individual's perception of appetite should also be taken into account. For some people, avoiding long periods of fasting prevents severe appetite declines. For others, structured, less frequent meals provide greater satisfaction.

For someone trying to lose weight, it's often recommended to limit snacking and prioritize satisfying foods. Constant snacking can make it more difficult to quantify a calorie deficit, making it easy to overindulge and thwart your weight loss goal.

In any case, it's vitally important to understand both physical and emotional hunger and to tailor meal planning to a personalized dietitian .

The above analysis is limited to individuals who, despite leading an active lifestyle, do not regularly engage in sports. However, if we focus on those who engage in moderate sports (e.g., working out at the gym several times a week, running short distances, recreational cycling, etc.), nutrition plays a role in supporting performance and recovery, even if these are not elite athletes.

In fact, some studies suggest that for physically active people, eating more frequently can help optimize certain aspects. Specifically, keeping total calorie intake constant and distributing it across multiple meals can enhance athletic performance, improve body composition (more lean mass, less fat mass), and support recovery after exercise.

Organizations such as the International Society of Sports Nutrition recommend that athletes on a weight-loss regimen consume small, frequent protein meals to mitigate muscle loss.

Snacking between meals does not speed up metabolism or guarantee weight gain or loss, but it could influence insulin levels, appetite control, and the overall quality of the diet .

Therefore, snacking will be considered beneficial or harmful depending on the frequency (moderate vs. continuous), the quantity (small portions vs. binge eating), the quality of the snack (nutritious vs. “empty calories”), and individual needs.

Using the practice of snacking to our advantage involves knowing when it's best to do it and when it's best to refrain, always paying attention to our body's signals and common sense.

(*) Academic Director of the Master's Degree in Precision Nutrition and Nutritional Epidemiology, Unir

(**) It is a non-profit organization that seeks to share ideas and academic knowledge with the public. This article is reproduced here under a Creative Commons license.