There is a large amount of fad dietary advice regarding which foods will fill you up. Holt et al. had an idea which was elegant in its simplicity: take a ton of people, and force them to eat some foods. A few hours later, place them in front of a buffet. The more people eat from the free buffet, the less full they must be.
There are some interesting confounds - for example, jelly beans seem to really fill people up. The researchers surmised that eating such large numbers of jelly beans made people too sick to keep eating.
Nonetheless, this gives us a nicely empirical measure of how full foods make you. We can then figure out what the cheapest food to eat is (assuming a full stomach is your goal).
| Food | Cost of 100 units of satiation (cents) | Cost of 100 calories (cents) |
|---|---|---|
| Cod | 173 | 400 |
| Ground Beef | 20 | 36 |
| Baked Beans | 18 | 31 |
| Eggs | 12 | 18 |
| Lentils | 10 | 13 |
| Wheat Bread | 9 | 18 |
| Potatoes (Red) | 8 | 26 |
| White Pasta | 7 | 8 |
| Whole Grain Pasta | 5 | 9 |
| Rice | 4 | 6 |
Methodology
I used Peapod to find the prices of everything. In the event that there were multiple products in a category, I chose the cheapest. The original paper was not terribly specific (is "beef" ground beef? lean? steak?) but there was not a large difference between price per calorie of different types of food at the very cheap end, so this shouldn't matter too much. The only significant issue was that cod is vastly more expensive than anything else (probably due to overfishing); if any potential experimenters are out there, I would be interested in seeing the satiety index of cheaper fish like tuna. (Although if canned tuna were as satiating as cod, it would have a rating here of 44, which would still make it twice as expensive as beef!)
Using the price and nutritional information, I calculated the price per calorie. The satiety index tells us the satiety per calorie. Using (Price / Calorie) * (Calorie / Satiety) we can find Price / Satiety. This is the number presented here. Numbers are hundredths of cents per unit of satiety.
Raw data can be found here.
Conclusions
Unsurprisingly, vegetable-based foods are much cheaper. A less obvious conclusion is that broad groups of foods do not have the same cost effectiveness - for example, baked beans cost almost as much as beef, whereas lentils are half beef's cost.
A frugal meal of rice and lentils has three times the cost effectiveness of a meal of beef, and is an order of magnitude more effective than anything involving fish.
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