What Keeps You Full the Most? The Science of Satiety

October 29, 2025 •

2 min read

According to a 1995 study published in the European Journal of Clinical Nutrition, boiled potatoes scored highest on the Satiety Index, proving more filling than other common foods. Understanding what keeps you full the most can revolutionize how you manage your appetite and support your health goals.

Quick Summary

This article explains the core principles of satiety, detailing the roles of protein, fiber, water, and energy density in controlling hunger. It provides a list of science-backed, highly-filling foods and contrasts them with less satiating options to help make more informed dietary choices.

Key Points

Protein is the Most Satiating Macronutrient: Consuming protein-rich foods increases levels of hormones that signal fullness while decreasing hunger hormones like ghrelin.
Fiber Adds Volume and Slows Digestion: Foods high in fiber, particularly soluble fiber from sources like oats and beans, swell in the stomach to create a prolonged sense of fullness.
Boiled Potatoes Scored Highest on Satiety Index: Studies show that boiled potatoes provide a high level of satisfaction for their calorie count due to their volume and water content.
Low Energy Density Foods Fill You Up for Fewer Calories: Eating foods high in water and fiber, like vegetables and broth-based soups, stretches the stomach and promotes fullness without excessive caloric intake.
Avoid Refined Carbs and Sugary Drinks: Processed foods and sugary beverages are rapidly digested, leading to blood sugar fluctuations and quick return of hunger.
Stay Hydrated to Manage Appetite: Mild dehydration can be mistaken for hunger, so drinking plenty of water can help regulate appetite and overall calorie intake.

The Science of Satiety and Fullness

Understanding what keeps you full the most requires distinguishing between fullness (physical stomach capacity) and satiety (feeling satisfied and not hungry). The most effective foods promote both feelings. Key factors influencing satiety include macronutrient composition, fiber content, energy density, water content, and chewing time.

The Dominant Role of Protein

Protein is generally considered the most satiating macronutrient. It helps regulate hunger hormones, decreasing ghrelin and increasing GLP-1, PYY, and CCK, which signal fullness. Protein also has a higher thermic effect and digests more slowly, leading to sustained fullness.

Fiber: The Volume and Timing Champion

Fiber is crucial for satiety, adding bulk and activating fullness signals in the stomach. Soluble fiber, found in foods like oats and beans, forms a gel, slowing digestion and prolonging fullness. Insoluble fiber adds bulk and supports digestion.

The Surprising Power of Water and Volume

The volume of food significantly impacts fullness, a principle central to the Volumetrics approach. High-water, high-fiber foods like soups and vegetables allow for larger portions with fewer calories, physically stretching the stomach.

Foods That Keep You Full the Most

Highly-satiating foods include:

Boiled Potatoes: Ranked highest on the satiety index due to volume.
Eggs: Protein-rich, linked to reduced calorie intake later in the day.
Oatmeal: Excellent source of soluble fiber for a filling breakfast.
Fish: High in protein and healthy fats, promoting satiety.
Legumes: Offer a powerful combination of plant-based protein and fiber.
Greek Yogurt: Protein-dense and effective for curbing hunger.
Soups: Broth-based soups provide volume with high water content.

What to Limit for Lasting Fullness

Foods low in protein or fiber and rapidly digested offer less lasting fullness:

Refined Carbohydrates: White bread and pastries digest quickly, causing blood sugar fluctuations.
Sugar-Sweetened Beverages: Lack fiber and bulk, providing empty calories.
Processed Snacks: High in energy density but low in satiety-promoting nutrients.

Comparison Table: Satiating Foods vs. Low-Satiety Foods


Feature	Highly Satiating Foods	Low-Satiety Foods (Refined/Processed)
Protein Content	High	Low to none
Fiber Content	High	Low or processed away
Water/Volume	High	Low
Energy Density	Low	High
Digestion Speed	Slows down digestion	Rapidly digested
Blood Sugar Effect	Promotes stable blood sugar	Can cause blood sugar spikes and crashes
Chewing Required	Often requires more chewing	Less chewing, easier to consume quickly
Hormonal Effect	Boosts satiety hormones	Less impact on satiety hormones

Conclusion: Your Strategy for Lasting Fullness

To maximize satiety, focus on meals combining high protein and high fiber, supplemented with water-rich vegetables. Prioritize whole, minimally processed foods that require chewing. Include lean protein and fiber from vegetables or legumes. Staying hydrated is also key, as thirst can mimic hunger. Implementing these strategies can help manage hunger and promote satisfaction. For further information, consider resources like the World Health Organization's healthy diet guidelines.(https://www.who.int/news-room/fact-sheets/detail/healthy-diet)

Frequently Asked Questions

Protein is the macronutrient that keeps you full the longest. It is digested more slowly than carbohydrates and fats and has a greater impact on hormones that control appetite, such as ghrelin and GLP-1.

No, all carbohydrates are not equally filling. Complex, high-fiber carbohydrates found in whole grains and vegetables are much more satiating than refined carbohydrates found in white bread and sugary snacks, which are digested quickly.

Drinking water can help you feel full because your stomach registers the volume of liquid, sending fullness signals to the brain. Sometimes, thirst is mistaken for hunger, so staying hydrated can prevent unnecessary snacking.

Healthy fats can contribute to lasting satiety by slowing down digestion, though they have a lower immediate impact on fullness compared to protein and fiber. Moderate portions of healthy fats from sources like avocado, nuts, and fish are beneficial.

Fullness is the physical sensation of having a full stomach, while satiety is the state of mental and hormonal satisfaction after a meal. You can be full without being satisfied, but highly satiating foods promote both sensations.

Yes, soups and other high-volume, liquid-based meals can be very filling. The high water content and physical volume can stretch the stomach, triggering fullness signals effectively. Broth-based soups are generally more effective than creamy, high-calorie versions.

Processed foods are often low in protein and fiber but high in refined carbs, sugar, and unhealthy fats. They are digested quickly, leading to rapid blood sugar spikes and crashes that trigger hunger again shortly after eating.