What Food Fills You the Longest? The Science of Satiety

January 4, 2026 •

4 min read

According to a 1995 study published in the European Journal of Clinical Nutrition, boiled potatoes were found to be the most filling food, with a satiety index score over three times higher than white bread. This surprising finding, along with other research, has led to a deeper understanding of what food fills you the longest and the key factors that contribute to lasting satisfaction.

Quick Summary

This article explores the nutritional components and food characteristics that promote long-lasting fullness. It discusses the roles of protein, fiber, and volume, identifies top-ranking satiating foods, and provides practical advice for incorporating them into your daily meals.

Key Points

Protein is Most Satiating: Lean proteins like fish and eggs are most effective at reducing hunger and increasing feelings of fullness due to their effect on hunger hormones.
Fiber Adds Bulk and Delays Digestion: High-fiber foods, such as oats and legumes, promote lasting fullness by slowing down the digestive process and physically filling the stomach.
Energy Density Matters: Low-energy-density foods (high in water and fiber, low in calories) like vegetables and soups allow you to eat larger portions for fewer calories, enhancing satiety.
Boiled Potatoes are Surprisingly Powerful: A 1995 study ranked boiled potatoes as the most satiating food tested, largely due to their high water content and specific type of starch.
Whole Foods Beat Processed: Unprocessed foods naturally contain more fiber and water, making them far more effective at curbing hunger than processed snacks, which are often high in calories and low in volume.
Combine Key Nutrients: The most powerful effect on satiety comes from combining protein, fiber, and healthy fats in a single meal, as found in foods like nuts.
Mindful Eating Enhances Satiety: Paying attention to your food's texture and eating slowly gives your brain time to register fullness signals, preventing overeating.

The Science Behind Feeling Full

Feeling full, or satiety, is a complex process influenced by several factors. The most powerful determinants of a food's ability to keep you satisfied are its protein content, fiber, and overall energy density. Understanding these components is the first step toward making smarter, more satisfying food choices.

The Satiating Power of Protein

Protein is widely regarded as the most satiating macronutrient. It reduces levels of ghrelin, the body's primary hunger hormone, while simultaneously increasing satiety hormones like PYY and GLP-1. Protein also has a higher thermic effect than carbs and fat, meaning your body burns more calories digesting it, which further contributes to a feeling of fullness.

The Crucial Role of Fiber

Dietary fiber adds bulk to your meals without adding significant calories. This bulk fills up the stomach, triggering stretch receptors that signal the brain that you are full. Soluble fiber, in particular, slows down the digestion process, meaning your stomach empties more gradually and your blood sugar remains more stable, preventing the rapid crashes that lead to renewed hunger.

The Importance of Energy Density

Energy density refers to the number of calories in a food relative to its weight. Low-energy-density foods, which typically contain a high percentage of water and fiber, can be consumed in larger volumes for fewer calories, making them incredibly filling. Think of a large salad versus a small bag of chips; the salad provides more volume for the same number of calories, making it more satiating. Conversely, high-energy-dense foods, like processed snacks and fast food, pack a lot of calories into a small serving and are less effective at curbing hunger.

Top Foods That Fill You the Longest

Based on scientific research and the satiety index, some foods consistently rank high for promoting long-lasting fullness.

Boiled Potatoes: Topping the satiety index, boiled potatoes offer a high volume and a type of starch that helps with fullness.
Eggs: A protein-rich breakfast of eggs has been shown to reduce calorie consumption throughout the rest of the day.
Oatmeal: The soluble fiber, beta-glucan, in oats creates a gel-like substance in the stomach that promotes fullness and delays gastric emptying.
Fish: High in quality protein and often rich in omega-3 fatty acids, fish is extremely satiating.
Legumes: Beans, lentils, and chickpeas are loaded with both fiber and protein, making them a powerful combination for curbing hunger.
Greek Yogurt: This thick, high-protein dairy product is more satiating than regular yogurt and helps control appetite.
Soups: Research has shown that soups, even pureed varieties, can be more filling than the same ingredients eaten as a solid meal, likely due to a combination of volume and slowed stomach emptying.

Comparison: Filling Foods vs. Less Satiating Foods

To illustrate the difference, here is a comparison of common food items and their satiating effects.


Food Category	Example	Key Satiety Factors	Effect on Hunger	Long-Term Fullness
High-Satiety	Boiled Potatoes	High water content, resistant starch	Strong reduction	High
High-Satiety	Fish (Ling)	High protein, omega-3 fats	Strong reduction	High
High-Satiety	Greek Yogurt	High protein, thick texture	Strong reduction	High
High-Fiber Carbs	Oatmeal	Soluble fiber (beta-glucan), volume	Moderate reduction	Moderate to High
High-Fat Processed	Croissant	Low protein, low fiber, high fat	Weak reduction	Low
Refined Carbs	White Bread	Low fiber, rapid digestion	Short-term reduction	Very Low

Practical Tips for Staying Full Longer

Prioritize Protein First: When building a meal, start with a source of lean protein like chicken, fish, or legumes. This helps establish satiety from the beginning.
Embrace Fiber: Add plenty of non-starchy vegetables to your plate, along with whole grains like oats or quinoa, to boost fiber and volume.
Don't Fear Healthy Fats: While too much fat can be less satiating, healthy fats from nuts, seeds, and avocados, combined with fiber and protein, send strong satiety signals to the brain.
Choose Whole Foods Over Processed: Whole, unprocessed foods have a higher satiety index than their processed counterparts. A baked potato is far more filling than french fries, and whole fruit is better than juice.
Drink Water: Sometimes thirst is mistaken for hunger. Staying hydrated with water or broth-based soups can help you feel full.

The Role of Psychology and Mindful Eating

Beyond the physiological effects of food, the psychological experience of eating also plays a role in satiety. Chewing your food thoroughly, savoring each bite, and eating slowly allows your brain enough time to register the feeling of fullness. Eating until you are comfortably satisfied, rather than uncomfortably stuffed, is a key component of mindful eating and long-term hunger management. Focusing on the texture, smell, and taste of your food also enhances satisfaction. For example, the thick, creamy texture of Greek yogurt can feel more indulgent and satisfying than a thin, sugary alternative, despite having fewer calories.

Conclusion: Your Toolkit for Lasting Fullness

Ultimately, the key to determining what food fills you the longest lies in a combination of nutritional components and mindful eating practices. By prioritizing meals and snacks that are high in protein and fiber, have a low energy density, and are made from whole, unprocessed ingredients, you can control your appetite more effectively. Incorporating foods like boiled potatoes, eggs, fish, oats, and legumes provides a solid foundation for building satisfying meals that keep you full for hours. Paired with conscious, slow eating habits, this approach empowers you to manage your hunger and sustain a healthy diet. To dive deeper into the science of satiety and weight management, a great resource can be found at the National Institutes of Health(https://www.nih.gov/).

Frequently Asked Questions

According to the satiety index developed by Australian researchers in 1995, boiled potatoes are the most filling food, scoring the highest among the 38 foods tested.

While both are crucial for satiety, protein is often considered the most satiating macronutrient, as it directly impacts appetite-regulating hormones. Fiber works by adding bulk and slowing digestion. For the best effect, combine both in your meals.

Foods with low satiety scores are typically highly processed, low in protein and fiber, and high in sugar or unhealthy fats. Examples include cakes, croissants, and white bread, which digest quickly and do little to curb hunger.

Whole fruit, rich in fiber and water, can be quite filling. However, fruit juice has had most of its fiber removed and is less effective at promoting lasting fullness. The whole fruit is always the more satiating option.

To make your breakfast more filling, prioritize protein and fiber. Excellent choices include eggs, oatmeal topped with nuts and seeds, or Greek yogurt with berries. This combination helps control hunger throughout the morning.

Cooking method can significantly impact satiety. For example, a boiled potato is much more filling than french fries because the frying process adds fat, increasing its energy density and reducing its ability to satisfy hunger.

Yes. While liquids are often less filling than solids, soup is an exception. Studies have shown that soups, especially those with some texture, can stay in the stomach longer and promote greater feelings of fullness compared to solid meals with the same ingredients.