Is feeling full simply a matter of eating enough calories? Not quite. Experience shows: A donut may contain more energy than a big bowl of vegetable soup – but often it’s the soup that truly makes us feel full. Why is that?
Satiety is a complex interplay of body awareness, digestive processes, hormones and even eating behavior. And it cannot be measured by calories alone.
1. Fiber – fullness through volume, not Calories
Fiber contains little to no usable energy – yet it’s a true hunger-buster. Why? Because it binds water, swells in the stomach and creates a sense of fullness without adding a heavy load.
- It stretches the stomach, sending a signal to the brain: “I’m full – you can stop now.”
- It slows digestion, resulting in a steadier rise in blood sugar – and more consistent energy levels.
- It promotes gut health which can influence eating behavior over time (via the so-called gut-brain connection).
Typical sources: whole grains, legumes, vegetables, fruits with skin – or simple additions like flaxseed or psyllium husks in your breakfast cereal.
2. Eating speed – eating slowly means feeling full sooner
How we eat is almost as important as what we eat. Satiety takes time – about 15 to 20 minutes for the brain to register that enough food has been consumed. If you wolf down your meal in five minutes, your body hasn’t even had a chance to send out fullness signals.
Eating slowly and mindfully:
- Supports the perception of internal cues
- Enhances enjoyment (which reduces the drive for “extra rewards”)
- Lowers the risk of overeating on autopilot
Practical tips: Count your chews, put down your utensils between bites, take conscious pauses – or even try eating with your non-dominant hand.
3. Volume – more space, less density
Foods with high volume and low energy – like salads, soups and vegetables – create a pleasant feeling of fullness without packing in many calories. This low energy density is a key to lasting satiety.
Why it works:
- The stomach stretches before too much energy is consumed
- The meal appears larger, which contributes to psychological satiety
- Pairing with warm dishes (e.g., soup as a starter) further slows eating pace
So volume isn’t just about filling space – it’s also a powerful signal to our hunger and satiety systems.
4. Hormones – when leptin, ghrelin & Co. weigh in
Every feeling of satiety involves a hormonal cocktail, especially two players are important:
- Ghrelin – the “hunger hormone” from the stomach. It rises before meals and drops afterward.
- Leptin – the “satiety hormone” from fat tissue. It signals long-term energy availability.
Other hormones like insulin, peptide YY and GLP-1 also play a role – and they respond strongly to what we eat. A meal made of sugar and white flour (fast carbs) causes blood sugar and insulin to spike – and then crash. The result: no lasting satiety.
More protein, more fiber, more healthy fats = more hormonal stability – and more sustainable satiety.
Satiety is multidimensional – and malleable
Satiety doesn’t come from a calculator – it happens in the body, the mind and through experience. Calories alone say little about how satisfying a meal truly is. If you only focus on numbers, you miss the bigger picture. Because true satiety is more than just a full stomach. It is a state of balance – physically and emotionally.
- Rolls, B. J. (2009). The relationship between dietary energy density and energy intake. Physiology & Behavior, 97(5), 609–615. https://doi.org/10.1016/j.physbeh.2009.03.011