The purpose of this blog, “What is Satiety and How Does it Work”, is to help you understand the factors that influence fullness, explain how it can help you lose body fat as well as answer some commonly asked questions.
Satiation is what signals us to stop eating a meal.
Satiety is how satisfied we are in between meals.
We are talking about feeling full and staying full.
The reason it’s important to understand the factors that influence both of these, is that it can help us build our meals in a way that helps us satisfy hunger, stay in control of our appetite and manage our calorie intake, if we have a fat loss or weight maintenance goal.
It can help you improve your meals by making them more filling, take your mind off food, lose weight and reduce hunger. Additionally, reducing feelings of hunger may have psychological and cognitive benefits by reducing preoccupying thoughts of food and emotions associated with feeling hungry (hangry). [12]
So if you want to lose weight without being hungry, read on.
The main points of satiety:
Understanding the factors that affect satiety and satiation can help us manage and control our energy intake.
Protein seems to have a greater effect on satiety than the other macronutrients. A minimum of 20g of protein per meal seems to be the sweet spot.
Food volume is important in the satiety response and may be more important than specific macronutrient content.
Fibre has a positive effect on feeling full between meals.
‘Lower calorie per bite’ foods appear to be more satiating than higher‐energy density foods.
Sleeping 7-9 hours per night can increase satiety.
Eating slowly, without distractions and chewing your food a little bit more can help.
Understanding is one thing, actually listening to your hunger signals is going to be the main thing.
Why are satiation and satiety important?
If you can learn to listen to these signals, it can help limit calorie intake helping you with a fat loss and/or weight maintenance goal because satiation and satiety can help us control our appetite and limit our intake of energy. Satiation is the process that causes us to stop eating; satiety is the feeling of fullness that continues after eating, reducing further eating. Both are important in controlling energy intake. [1]
What does satiety mean?
Satiety is best described as is the feeling of fullness after a meal. A meal that has increased satiety; has you feeling full between meals and may delay the time until you eat again.
Example:
High satiety meal @ 7am could mean you may not feel the need to eat again until 12pm.
Low satiety meal @ 7am could mean you may want/need to eat again at 9am.
What is the difference between satiety and satiation?
Satiation stops eating. Satiation = termination.
Satiety is the fullness after eating (between meals). Satiety = sobriety (been a while between drinks).
What signals satiety?
The measurement of satiation and satiety is complicated. Many factors besides just internal signals may influence appetite and calorie intake. Eg. physical factors such as body weight, age or gender, or behavioural factors such as diet or the influence of other people. [1]
There are more factors than just food composition that influence satiety. Reflect on the times when you feel more satisfied and less hungry, think about what individual factors may play a role in those situations such as the foods you eat, the people you’re with. Compare that to times when you feel less satisfied and more hungry, what factors are different in those settings?
How do satiation and satiety work?
Satiation and satiety are initially affected by sensory and cognitive factors including expectations of the meal, the taste, texture and smell of the food or drink.
Once food reaches the stomach and the stomach starts to stretch due to the food volume, the stomach sends a signal to the brain initiating satiation. As digestion continues in the intestines, hormones that promote satiation and satiety are released from the gut. [1]
The stretch of the stomach due to food volume is important to understand as you can learn to build meals with more volume and less energy. If you’re currently eating small meals but are always hungry, this could be a reason why. The signals of satiation and satiety aren’t being activated as well as they could be if the meal had more volume and took up more room in the stomach.
Which hormones promote satiety?
Ghrelin is the hunger hormone. When that is suppressed, we feel less hungry.
Leptin is the satiety hormone. When we activate that, we feel more satisfied and full (less hungry).
CCK stimulates satiation after a meal when nutrients enter the small intestine.
What has the largest impact on satiety?
A number of studies have shown that people consistently consume a similar weight of food each day, rather than a constant amount of energy [10]. Eg consistently consuming 2000 grams of food rather than 2000 Calories. This means that the lower the energy content of the foods eaten (lower calorie per bite), the lower overall energy intake may be and vice versa.
Example:
If someone usually eats a meal of 500g in weight it can have different calorie contents such as the graph shown below.
In this example all meals have the same food volume. If you’re wanting to feel fuller on less calories, look at adding higher volume lower calorie foods such as fruits and vegetables.
Overall, the characteristic of a food or drink that appears to have the most impact on satiety is its energy density. We like to refer to this as “calories per bite”. High‐fat foods tend to have a higher energy density than high‐protein or high‐carbohydrate foods, and foods with the highest water content tend to have the lowest energy density. High energy density = more calories per bite. Low energy density = fewer calories per bite. [1]
Examples:
Fruit has a lower energy density than chocolate.
Vegetables have a lower energy density than pasta.
Honey has a higher energy density than strawberries.
Olive oil has a higher energy density than avocado.
Potatoes have a lower energy density than rice.
White fish has a lower energy density than salmon.
The main factors of energy density are water and fat. Foods with the lowest calories per bite are those with the most water and least fat. Foods with the highest calories per bite are typically high in fat and low in water. Fibre can also help reduce calorie density.
The calorie density of foods and drinks can have a major impact on satiety and this may be more important than macronutrient composition in terms of enhancing satiety. [1]
Therefore if we can eat more foods that are lower calorie per bite, we can increase our satiety.
That’s why we like to promote the idea that you don’t have to eat less food volume to lose weight, just less calories.
Which macronutrient sustains satiety best?
Protein:
Most studies show that protein has a stronger effect on satiety than the same quantities of energy from carbohydrates or fats.
It increases satiety in one meal and over 24 hours. [6, 7] It was also shown to spontaneously lower energy intake, which can be important if you don’t weigh, measure and record your food intake. [8]
How much protein?
20g protein seems to be enough to maximise satiety. [9]
If you’re struggling to get full and stay full, check that your meals are hitting 20g protein minimum. If you don’t know how to do this, a little experiment with My Fitness Pal or another calorie counting app might be all you need to build more filling meals.
Carbs:
The effect of a carbohydrate on satiety depends on the volume and energy density of the carbohydrate and other aspects of the food such as fibre and water content. Eg. potatoes are more satiating than rice. If you’re looking for more filling meals, you might want to look for carb sources with water and fibre. More on fibre in the next point.
Fibre:
Most studies showed an effect of fibre on satiety and subsequent energy intake. The amount of fibre was important, and larger doses were more effective at promoting satiety and reducing energy intake. Fibre sources include fruit, vegetables, oats, barley and bread.
Fat:
Dietary fat affects satiety by slowing gastric emptying, stimulating the release of satiating gut hormones and suppressing the release of ghrelin. However, due to the low volume and high energy density of fats, they don’t initiate as much of a stretch response of the stomach as higher volume foods such as plants.
Alcohol:
Lack of satiety and actually stimulates appetite.
If you drink alcohol frequently, maybe a glass with dinner each night and feel like you are still hungry after your meal, be cautious with alcohol as appetite will be higher.
How does flavour affect satiety?
Increasing the flavour of food increases appetite, meal size, meal duration and eating speed. If portions are not controlled, the more tasty foods tend to be the least satiating and the least tasty foods the most satiating. Flavour tends to reduce satiation and satiety and leads to increased energy intake. [1]
This doesn’t mean we shouldn’t add flavour to our foods. It just means we need to be aware that the tastier they are, the more we may want to continue eating so portion control is going to be important. If you feel like you’re constantly hungry between meals and the food volume is already accounted for, play around with how much flavour is in your meals and try to find the sweet spot that helps increase satiety.
Another potential strategy could be to change the flavour with something like toothpaste or chewing gum after a meal to add an effort barrier to further eating.
Variety and Satiety
A number of studies have shown that the more options of food available at a single eating occasion, the more people will eat [11]. Another term known as sensory‐specific satiety (SSS), suggests the desire to eat a food that has already been tasted is significantly reduced compared with one that has not. It appears that reducing the variety of foods eaten can stimulate satiety via SSS. Offering a variety of foods seems to decrease satiety and increase energy intake within a meal. [1] ‘Sensory‐specific satiety’ is why we tend to have a “dessert stomach”.
Example:
If you have a plate of meat and potatoes and feel full, you probably won’t want to eat more meat and potatoes. That flavour is no longer desirable so you feel full. However when a new flavour that hasn’t been tasted in that meal yet, such as chocolate, is put in front of you, all those feelings of fullness might disappear.
Society and Satiety
The more people present at a meal, the more food is eaten compared to when eating alone.[1]
Social meals are an important part of our lives though so all this means is to be mindful of your portions and eating behaviours when with others. If you are eating more meals with others, can you focus on some other factors that increase satiety such as food volume, energy density, and mindful eating.
Speed and Satiety
A study on the eating behaviour of lean and obese individuals and found that obese subjects ate faster, took bigger spoonfuls and had a greater overall energy intake than lean subjects. [1] If you find that you’re a fast eater and it leaves you feeling hungry, try to slow your rate of eating down. Can you stretch it out to 15-20 minutes by putting your cutlery down in between bites, swapping hands, using chopsticks, etc.
Chewing and Satiety
Chewing your food more can significantly reduce hunger and promoting satiety. [2]
Most filling foods to prevent hunger
Some foods are more satiating than others. Those foods tend to be Protein and Plants. The foundation of our FNC meals. The graph below shows the satiety index of common foods.
The foods are compared to the satiety index of white bread as a baseline. Foods that are above the line offer more satiety, the foods below the line offer less. White potatoes rank highest meaning they leave us feeling really full in between meals, whilst croissants are lowest leaving us feeling quite hungry after being eaten.
A Satiety Index of Common Foods showing the least filling to most filling foods. Image credit: Ben Carpenter.
How to feel full?
Eat mindfully without distractions. There are some studies that show that being distracted when eating (commonly television) can make people less sensitive to signals of satiety and lead to increased energy intake. [1]
How does sleep affect satiety?
People who experience short sleep have reduced leptin (satiety) and elevated ghrelin (hunger).
[4]. Short sleep is anything less than around 7-9 hours per night. If you’re waking up and feeling like you could go back to sleep around 11am, and if you’re feeling constantly hungry throughout the day, you may be experiencing poor quality sleep.
Will satiety and satiation help you lose weight?
It can, if you listen to the signals and it helps you control your intake. However, although satiety and satiation have the potential to control energy intake, many people don’t listen to these signals or if they do, they override them. People override these signals by continuing to eat when they are full and eating when they aren’t hungry. Knowledge about foods, ingredients and dietary patterns that can enhance satiation and satiety is potentially useful for controlling body weight. However, this must be coupled with an understanding of other factors that influence eating behaviour, in order to help people to control their energy intake. [1]
The information in this blog on food volume, energy density, macronutrients and eating behaviours that increase satiety paired with an understanding of how to reduce your calorie intake can help you lose weight without feeling hungry and deprived of foods.
Note for muscle gain and athletes:
It’s worth noting that if you have a weight gain or sports performance goal, eating based on your hunger and fullness cues may not be ideal as you will have higher calorie requirements and it may be difficult to reach those targets if solely listening to these cues.
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REFERENCES:
[1] https://onlinelibrary.wiley.com/doi/full/10.1111/j.1467-3010.2009.01753.x
[2] https://www.sciencedirect.com/science/article/pii/S0031938415300317
[3] https://pubmed.ncbi.nlm.nih.gov/7498104/ - image source: Ben Carpenter
[4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC535701/
[5] https://pubmed.ncbi.nlm.nih.gov/29424405/
[6] https://pubmed.ncbi.nlm.nih.gov/16469977/
[7] https://pubmed.ncbi.nlm.nih.gov/16400055/
[8] https://pubmed.ncbi.nlm.nih.gov/16002798/
[9] https://pubmed.ncbi.nlm.nih.gov/25979566/
[10] https://pubmed.ncbi.nlm.nih.gov/10721885/