Why Am I Always Hungry? The Foods That Keep You Full Longer

Why Am I Always Hungry? The Foods That Keep You Full Longer
Are you constantly hungry even after you've just finished a meal? A new study reveals which foods are the best (and worst) at keeping you full longer.

I am sure you have heard of the satiety index by now. It's a list of the 38 most commonly eaten foods and their respective scores on satiety levels in the general population. Study participants were asked to eat certain foods and then rank their level of fullness 2 hours later.

While I commend the researchers for their work, I've found that some of the details from the study are not directly applicable for active athletes, bodybuilders, or gym-goers.

First, many of the foods used are not commonly eaten by us (jellybeans, ling fish, Sustain). Meanwhile, the list of foods does not include many common foods (chicken breast, peanut butter, Greek yogurt) in an athlete's diet. Since the participants may have been aged, obese, inactive, or exhibited other characteristics that generally aren’t associated with trained individuals, their reactions could be different from what we experience.

Lastly, the impacts of the foods were only assessed at the 2 hour post-consumption mark. I believe when many of us think about a need to feel full, we think about the immediate (“I am hungry and I want something to eat now!”) or the long-term (“I am eating lunch now and I want this meal to hold me over until dinner” or “I am eating my pre-bed meal and need it to last me overnight”).

Thus, I decided to conduct a study based on survey data to assess both the short and long term satiety effects of various foods. Short term satiety was defined as the period 30 minutes to 90 minutes following consumption. Long term satiety was defined as 5+ hours post consumption.

Why Am I Always Hungry? The Foods That Keep You Full Longer

All foods listed had their serving size adjusted so that calories were normalized (identical). In other words, the findings show satiety when you eat the same amount of calories from each food listed. All the participants themselves were recreationally active young men and women who ate these foods on a regular basis.

Satiety Case Study: The Good, The Bad, and The Ugly

I asked each participant to score 35 different foods for both short and long-term satiety on a scale of 0 to 9 (9 being the highest level of satiety). After getting the scores from each participant, I assessed each food based on macronutrient content (protein, fat, and carbs), volume, fiber, and sugar. I then conducted a multivariate modeling analysis to assess each of these factors' impact on satiety score. The results of the model suggest the following:

  • High volume foods equate to higher short term satiety levels, but their impact is relatively meaningless in the long term.
  • Protein and fiber increase both short and long term satiety levels.
  • Fat does not equate to any increases in short term satiety, but does result in increases in long term satiety. Fat-containing foods performed additionally well when accompanied with fiber (ex. Avocado would be better than oil).
  • Sugary foods result in lower satiety levels, unless the food also incorporates a high volume and fiber content (ex. Fruit would perform better than a sugary snack food or breakfast cereal).
  • Traditional “snack foods” performed very poorly in terms of both short and long term satiety.
  • Outlier: Potatoes - Scored extremely high in both short and long term satiety despite being a high carb food without significant levels of fiber. Future studies should be conducted on a compound found in potatoes known as resistant starch which could help to explain their high satiety index.
FRUITS Short Term Score Long Term Score
Apple 6 5.5
Orange 4.33 4.71
Berries 4.88 5
Banana 4.86 4.63
MEAT/DAIRY Short Term Score Long Term Score
Chicken Breast 5 5.25
Ground Beef 5 5.83
Steak 6.13 6.75
Whole Egg 5.88 6.25
Egg White 6.8 7.2
Whey 4.86 4.29
Casein 4 5
Greek Yogurt 5.75 6.29
Fruited Yogurt 5 3.5
Whole Milk 3.83 4.5
Cheese 3.17 4.17
Cottage Cheese (nonfat) 5.5 5.75
STARCHES Short Term Score Long Term Score
Baked Potato 5.86 6.75
Baked Sweet Potato 6.43 7.23
White Rice 4 3.5
Brown Rice 4.2 4.67
Oatmeal 5.5 6
Black Beans 3.83 4.67
White Bread 2.83 1.83
Whole Grain Bread 3.17 3.17
Pasta 4 3.83
SNACK FOODS Short Term Score Long Term Score
Sugary Cereal 1.33 1.29
Ice Cream 2.25 2.13
Store Bought Cookies 1.83 1.5
French Fries (fast food) 2.29 2.13
Doughnuts 2.5 2.13
Potato Chips 1.38 1.25
HIGH FAT FOODS Short Term Score Long Term Score
Peanut Butter 4.29 6
Nuts 3.71 5.57
Avocado 4 5.13
Olive Oil 1.26 1.57

Many of the results verify previous research showing the satiating benefits of both protein and fiber.1 Volume appears to be completely diminished in promoting satiety when we look at its effects in the long term. So while eating a massive 200 calorie salad may make you feel incredibly full in the short term, a small cup of beans may end up leaving you full for hours on end.

In fact, some research has even shown that eating foods in excessively large volumes will result in your stomach expanding beyond normal size. Once this food is partially digested and moves out of the stomach, you are left feeling starving afterwards as there is now a larger void needing to be filled than before.2

The low scores for snack foods support evidence showing higher quality nutrient dense foods promote fullness to a greater extent than snack foods generally will.3 We also see how even small volumes of high fat foods can have a long lasting effect on satiety, such as peanut butter or avocados.4

Why Am I Always Hungry? The Foods That Keep You Full Longer

I think in the future we could further studies to see if timing has any impact. For example, would certain foods promote overall satiety if they are eaten early in the morning, rather than right before bed?

Secondly, we should also examine how certain foods interact with each other. Each food on this list was assessed in isolation, but we rarely eat food in isolation. What happens when you eat nuts with fruit compared to eating chicken and rice? If we were to sum the scores of two foods listed above, would they always outperform any two foods with a lower sum score?  Or would the interaction of each combination of foods have a different impact?

Furthermore, can we score foods based on the resulting decrease in caloric intake later?  For example, a 2013 study found oatmeal resulted in significantly less calories eaten later in the day than an oat-based cereal of identical calories.5

Satiety: Short vs. Long Term

While many of the results of this study may not be earth shattering, I do think it is a good reminder of how we need to build the base of our diet. I think it also points to why many non-dieters have trouble keeping their caloric intake in check (i.e. they eat a higher % of low-satiating foods). In the end, a high-protein, whole food, and well-balanced diet will win out over the standard American cuisine consumed by many you may know.