I am wondering what makes some foods more filling than others? To better explain this question I think I need to get into a little bit of a story, please bear with me a moment. Lately I’ve been keeping a bit of a food diary. I read somewhere that it’s a good idea to write about how certain meals make you feel, how long till your next hungry, and what your appetite is like throughout the day. This was surprisingly insightful. I typically rotate a handful of different breakfasts, all 300-400 calories. Veggie egg white omelette with toast, ham & cheese egg white omelette with toast, shredded wheat, steel cut oats and canned baked beans on toast with egg (fried or poached). I’m an endomorph, with familial hypercholesterolemia, on a diet at the moment, hence the egg white. I’m always into discovering more variety but these are my staples. It’s no surprise that typically the higher protein foods are more filling. The omelettes (23-34g protein, 24-28g carbohydrates, 10g fat, 6-9g dietary fibre) keep me satisfied for up to 3 hours post meals. The oats go as far as an hour and a half for me, having the least amount of protein (9g, 65g carbs, 5g fats, 3g fibre). Shredded wheat does well, I’m satisfied for up to 3 hours as well despite it not being super rich in protein (16g, 63g carbs, 7g fats, 10g dietary fibre). Baked beans on toast with egg, which is actually not bad on protein, only keeps me satisfied for an hour an a half as well (21g protein, 47g carbs, 8-10g fat, 16g fibre). The other morning I tried something else. I had 1 portion of wholegrain porridge, yogurt and berries. The protein was right up there for this meal, the fibre too. But for some reason I was hungry in an hour and a half or less. So despite this meal being high in protein, as well as the baked beans, why is it not as filling as an omelette? What makes one food more filling than another? I don’t see it as being the fibre, volume, digestibility, sugar or GI ranking.
Hello and thanks for your question. It sounds like you have spent a lot of time analysing your diet and trying to find what works best for you. Regarding your question what makes one food more filling than another. Well there are a number of factors at play which you outlined in your question. Other than the protein and fiber you mentioned as making foods more filling, there is also fat content to be considered. The fat content of the meal also has an impact on the rate of digestion with a high fat meal being more slowly digested than a low or fat free meal. Normally food held in the stomach is released into the intestines within four hours, however a fat rich meal can be held in the stomach for six or more hours. In terms of fiber there is both soluble and insoluble fiber, these fibre’s are processed differently with soluble fiber slowing digestion. Whilst your records might show two different meals both contain ten grams of fiber, one meal might contains fiber of the soluble variety leading to the feeling of fullness for longer. There are even psychological elements at play, when you have a meal that looks, smells and taste’s good this stimulates your digestive system, and in turn your stomach can secrete more acid. Have you ever eaten something very plain and dull without seasoning, such as plain tuna and pasta. You can get a feeling of fullness very quickly and this can last a long time. The time of day, your activity levels and also your previous meals can also have an impact. There is no one factor that decides the digestibility of a meal and how long the feeling of fullness you will experience, it is combination of all the points mentioned above.