What is the most filling thing in the world?

December 5, 2025 •

4 min read

According to the Satiety Index, created in a 1995 study published in the European Journal of Clinical Nutrition, boiled potatoes were the most filling food, with a score of 323% compared to white bread. This research introduced a way to understand how different foods affect feelings of fullness. The index showed differences in the satiating capacity of various foods, even when the calorie count was the same.

Quick Summary

This article discusses the science of satiety, exploring what makes foods filling and revealing top-ranked foods on the Satiety Index. Protein, fiber, water content, and energy density influence fullness, and there are strategies for building more satisfying meals.

Key Points

Boiled Potatoes are Number One: A 1995 Satiety Index study ranked boiled potatoes as the most filling food, scoring 323% compared to white bread.
Protein is Powerful: Protein is the most satiating macronutrient, helping to suppress hunger hormones and prolong feelings of fullness.
Fiber Adds Bulk: High-fiber foods, especially soluble fiber found in oats and legumes, slow digestion and keep you feeling full longer.
Water Increases Volume: Foods with high water content, like fruits and soups, fill the stomach and send fullness signals without adding excess calories.
Low Energy Density is Key: Foods with fewer calories per gram, such as fruits and vegetables, allow for larger, more satisfying portions.
Processing Reduces Satiety: Highly processed, palatable foods like pastries and candy are generally less filling and easier to overeat than whole, unprocessed foods.
Strategic Snacking Matters: Opting for high-satiety snacks like Greek yogurt or apples can help curb hunger between meals effectively.

The Science of Satiety: Understanding Fullness

Satiety, or feeling full, involves physical and hormonal signals that tell the brain when to stop eating. The Satiety Index, developed by the University of Sydney, scientifically compares the ability of different foods to satisfy hunger. Participants were given equal-calorie servings (240 calories) of 38 common foods, and hunger levels were measured over two hours. The findings revealed that a food's composition and characteristics matter more than its calories for feeling full.

The Satiety Index Explained

The Satiety Index uses white bread as a baseline (100%). Foods with higher scores are considered more filling. The index revealed a surprising winner and several high-ranking foods, challenging common beliefs about which foods truly satisfy hunger.

Key Factors Influencing Fullness

The most filling foods share characteristics that trigger satiety signals:

High in Protein: Protein is the most satiating macronutrient. It affects hormones like ghrelin (hunger hormone) and GLP-1 and PYY, which promote fullness. Protein also has a high thermic effect, meaning the body burns more calories digesting it.
High in Fiber: Fiber adds bulk to meals and slows digestion. This delays stomach emptying, leading to sustained fullness. Both soluble and insoluble fiber help.
High in Water Content: Foods with high water content, like fruits and soups, increase the food volume in the stomach without adding many calories. This physical stretching signals fullness.
Low Energy Density: This refers to foods with fewer calories per volume or weight. Eating low-energy-density foods allows larger portions and feeling fuller on fewer calories. These foods are high in water and fiber and low in fat.
Lower Palatability: Less processed foods are often more satiating than highly processed, hyper-palatable options. Foods engineered to be sweet, salty, or fatty are easy to overeat, while whole foods are more likely to signal satisfaction.

Top Contenders: The Most Filling Foods

The Satiety Index identified several foods that excel at promoting fullness per calorie. Here are some of the highest scorers:

Boiled Potatoes: Topped the index with 323%. Their high water content, moderate fiber, and resistant starch contribute to their effect.
Ling Fish: Ranked second with 225%. Fish is a source of lean protein, which is known for its satiating properties.
Porridge/Oatmeal: Scored 209%. The soluble fiber, beta-glucan, absorbs water, forming a gel in the stomach, promoting fullness.
Apples and Oranges: Scored 197% and 202% respectively. These fruits have high water and fiber content, adding bulk.
Legumes (Baked Beans and Lentils): Packed with fiber and plant-based protein, baked beans scored 168% and lentils 133%. They have a low energy density, making them filling.
Eggs: Rich in protein, eggs scored 150%. Studies show an egg breakfast can reduce calorie intake later.
Beef: Lean cuts of beef scored 176% due to their high protein content.

Comparison of Satiating Foods

Comparing some of the most and least satiating foods based on the Satiety Index study. This shows the importance of food quality.


Food Item	Satiety Index Score (vs. White Bread)	Key Characteristics	Impact on Fullness
Boiled Potatoes	323%	High water content, moderate fiber, resistant starch	Extremely filling, very low energy density
Croissant	47%	Low water, high fat, high palatability	Not very filling, easy to overeat
Ling Fish	225%	High lean protein, moderate fat	Very satiating, low energy density
Doughnuts	68%	High sugar, high fat, low fiber, high palatability	Not very filling, triggers cravings
Oatmeal (Porridge)	209%	High soluble fiber, high water absorption	Very filling, sustained energy release
Ice Cream	96%	High sugar, high fat, low fiber	Moderately filling, but often consumed in large quantities

Practical Strategies for Maximizing Fullness

Incorporating highly satiating foods into a diet is a strategy for managing appetite and maintaining a healthy weight.

Building a Satiating Meal

Protein is key: Start with a high-protein base, like lean fish, chicken, or lentils.
Add fiber: Add fiber-rich vegetables, like broccoli or sweet potatoes.
Choose whole grains: Opt for whole grains instead of refined ones. Quinoa or brown pasta are good.
Include healthy fat: A small amount of healthy fat from avocado or nuts can enhance satisfaction.

Snacking Smart for Sustained Energy

Choosing the right snacks can prevent overeating during meals. Instead of low-satiety items, opt for:

Greek yogurt with berries.
Apple slices with nuts.
Air-popped popcorn.
Cottage cheese with cucumber.

For more in-depth information on the original study, you can review the abstract here.

Conclusion: The Ultimate Satiety Strategy

While the boiled potato may be the winner on the Satiety Index, the secret to feeling full is understanding the characteristics that make a food satiating. A meal with protein, fiber, and water, with a low energy density, will provide longer-lasting fullness than a meal high in fat and sugar. Incorporating these food properties into a daily routine can better manage hunger and support long-term health and weight goals. The most filling thing in the world isn't a single food but a balanced approach to eating.

Frequently Asked Questions

Boiled potatoes are exceptionally filling due to their high water content and the presence of resistant starch, especially when cooled. This combination increases the bulk of the food without adding calories and slows down digestion, promoting a longer-lasting feeling of fullness.

Both protein and fiber are crucial for satiety. Research shows protein to be the most satiating macronutrient, impacting hunger hormones directly. However, fiber provides bulk and slows digestion, working together with protein to maximize fullness.

Energy density refers to the number of calories relative to a food's weight. Low-energy-density foods, which are typically high in water and fiber, allow you to consume a larger volume of food for fewer calories. This fills your stomach and triggers fullness signals more effectively than calorie-dense foods.

No. Complex carbohydrates found in whole grains, legumes, and certain vegetables like potatoes are very effective for satiety because of their fiber content and slower digestion time. Simple, refined carbohydrates like white bread and pastries, however, are less filling.

Yes. The way a food is prepared can significantly alter its satiating effect. For instance, a boiled potato is highly satiating, but when fried, its fat content and energy density increase, making it less filling per calorie. Opting for boiling, steaming, or baking generally preserves the natural filling properties of foods.

The Satiety Index compares foods based on their ability to satisfy hunger after consuming a 240-calorie portion. White bread is used as the baseline (100%), and other foods are given a percentage score relative to it. A higher score means the food is more filling.

To build a more filling meal, focus on combining foods rich in protein, fiber, and water. A balanced approach might include a lean protein source (like fish), a high-fiber vegetable (like broccoli), and a whole grain (like quinoa or brown rice). Eating slowly can also help your body register fullness more effectively.