Potatoes Beat Croissants in the Fullness Factor

New Study Reveals Why Some Foods Curb Hunger Better Than Others

Feeling unsatisfied just an hour after eating? It’s not necessarily a lack of willpower. A decades-old study, gaining renewed attention, shows that what you eat matters far more than simply counting calories when it comes to feeling full and energized.

The Satiety Index: A Surprising Ranking

Researchers at the University of Sydney conducted a fascinating study in 1995. They gave participants 240-calorie portions of 38 common foods and then monitored how long it took before they felt hungry again. Each food received a Satiety Index score, comparing its fullness-inducing power to that of white bread (set at 100). Foods scoring higher than 100 were more filling, while those below were less.

The results were striking. Boiled potatoes topped the list, while the humble croissant landed at the very bottom. This isn’t just about calories, protein, or texture; it’s a complex interplay of weight, volume, protein, fiber, and water content—physical signals that tell your body, “enough.”

Why Croissants Fail to Satisfy

Croissants are a disaster for sustained fullness. They are low in protein, a crucial nutrient for fighting hunger. They also lack fiber, which adds bulk to the gut and slows digestion. Furthermore, their high fat content and low water content mean they slip through the digestive system quickly, providing minimal signals of satisfaction.

Even the pleasurable experience of eating a croissant can work against you. Highly palatable foods—rich, sweet, or crispy—tend to encourage overeating.

“Foods that contain large amounts of fat, sugar, and/or starch have low Fullness Factors, and are much easier to overeat. Foods that contain large amounts of water, dietary fiber, and/or protein have the highest Fullness Factors. These high-FF foods, which include most vegetables, fruits, and lean meats, do a better job of satisfying your hunger,”

—The Study Authors

Foods That Keep You Full Longer

Unprocessed foods generally excel at promoting satiety. But it’s not just fruits and vegetables; oatmeal, eggs, and cheese also rank highly. According to the CDC, over 40% of US adults are obese, highlighting the need for effective strategies to manage hunger and weight. (CDC Obesity Statistics)

• Boiled potatoes (323): Surprisingly filling for their calorie count, thanks to their water and fiber content.
• Oatmeal (209): A warm, slow-digesting source of fiber.
• Eggs (150): High in protein and easily portable.
• Popcorn (154): Air-popped and unbuttered, it’s a low-calorie, bulky snack.
• Whole grain breads (157): Fiber makes a significant difference.

Beyond Willpower: A Shift in Focus

For years, the focus has been on calories and macros, often neglecting the crucial element of satiety. Many wellness trends prioritize protein powders and intermittent fasting, yet people still struggle with hunger and cravings. This study underscores the importance of choosing foods that genuinely satisfy, rather than simply restricting intake.

The key isn’t necessarily to eliminate enjoyable foods like croissants, but to understand their limitations and prioritize those that provide lasting fullness. By focusing on satiety, we can move beyond restrictive dieting and cultivate a more sustainable, enjoyable relationship with food.