The calorie density of a food is the amount of energy, or calories, provided by a certain weight of that food. Calorie density is typically stated as calories per gram. Calorie sparse foods contain few calories for a relatively large amount of food, while calorie-dense foods contain a lot of calories for a relatively small amount of food.
For example, 100 grams of cucumber contains a mere 15 calories, meaning that it’s calorie density is 0.15 calories per gram. Macadamia nuts, on the other hand contain a whopping 716 calories per 100 grams, or 7.16 calories per gram. So we can say that cucumber is calorie-sparse, while macadamia nuts are calorie-dense.
Below is an illustration of what 100 calories worth of several different foods look like. As you go from top to bottom, the foods increase in calorie density — with the cucumber being the least calorie-dense food in the list, and the macadamia nuts being the most calorie-dense food in the list.
So what makes foods calorie-sparse or calorie-dense? While several factors can affect a food’s calorie density, calorie-sparse foods are generally higher in water and fiber content, and lower in fat than calorie-dense foods. Conversely, calorie-dense foods are usually drier and higher in fat.
An example of how water content impacts calorie density can be seen when comparing dried fruit to fresh fruit. When comparing equal weights of each, raisins are much more calorie-dense than grapes. Similarly, an example of how fat content impacts calorie density can be seen when comparing different cuts of beef. When comparing equal weights of each, fatty cuts of beef are more calorie-dense than lean cuts of beef.
Why Calorie Density Matters
Though calorie density can be an important consideration for anyone, it becomes even more relevant when trying to gain or lose weight. The reason ultimately comes down to hunger and satiety signals, and how each of these impacts our goals.
Calorie Density and Weight Loss
We know that in order to lose body fat, you need to be in a caloric deficit. Unfortunately, once the deficit has grown large enough or has been sustained over a long period of time, increased hunger and preoccupation with food can start to threaten dietary adherence.
So part of getting ripped will involve managing hunger, which is where choosing higher-volume, calorie-sparse foods comes in. But that’s not to say that eating for volume will make being in a prolonged deficit pleasant — because it won’t. Nor will it completely relieve you of hunger, as the mechanisms that regulate hunger are more complex enough that we can’t completely override them just by putting more water and fiber in your stomach.
Having said that, eating larger volumes of calorie-sparse foods rather than smaller quantities of calorie-dense foods might take the edge off the hunger enough that you may find it easier to adhere to your diet plan or targets. And since adherence is the number one factor in your success, anything we can do to nudge the odds in that direction is a win.
Calorie Density and Weight Gain
Calorie density is also an important consideration when you’re trying to gain weight. As we know, to build muscle, you need to be in an energy surplus. Unfortunately, a surplus can require an awful lot of food — sometimes more food than a person can comfortably eat in a day.
I know it might sound odd that anyone would have trouble eating enough to gain weight but, after a certain point, eating that much and that frequently really can become a chore. In situations like this, swapping out some calorie-sparse foods for some foods that provide more calories for less bulk. If you consider yourself a hard gainer, this tactic can help a ton.
Often, a “hard gainer” isn’t really a hard gainer — they just aren’t eating enough. Perhaps their appetite is poor. Perhaps they severely overestimate how much they’re eating. Or perhaps they just habitually consume a lot of calorie-sparse foods like fruits and vegetables. While fruits and vegetables are wonderful, they provide so much volume that someone without much of an appetite may struggle to get in enough calories. This works out great for dieters, but can make it tough for those trying to put on mass.
Calorie Density and Macronutrients
Below I’m going to show you visual comparisons of what 100 calories worth of various foods looks like. I’ve divided the photos into five groups of similar foods (proteins, fruits and vegetables, grains and starches, fats, and sweets and snacks) to make for a more accurate comparison. While some foods fit neatly into a single category, most foods have a bit of overlap between categories, since foods rarely contain only one macronutrient. Still, I tried to divide them up as best I could.
I’d also like to clarify that the portions pictured are not suggested serving sizes. Your serving size is ultimately up to you, and doesn’t necessarily need to be limited to a 100-calorie portion. The foods were only standardized to 100-calorie portions to make for a clear illustration of how they differ in volume for the same number of calories.
Protein provides 4 calories per gram. It is reported to be the most satiating of the macronutrients. So, getting enough protein with each meal may help you feel fuller longer. You may need to experiment to figure out how much protein per meal feels best for you. As a general rule of thumb, around 20 to 30 grams per meal is a great place to start.
Protein sources vary in calorie density primarily because of their fat content. The leaner the protein source, the more protein “bang for your buck” you’ll get. Two similarly lean sources of protein usually have roughly comparable calories.
For example, 93% lean beef and 93% lean turkey are very similar in calories. Similarly, 97% lean ground beef and 97% lean ground turkey are also similar in calories, but they both contain less calories than the 93% lean versions. As you can see below, you get more food volume for the same number of calories when you choose 93% ground beef over 85% ground beef.
Some proteins vary in calorie density because of their water content. Beef jerky is a good example. The process of drying the meat and removing the water makes the end product more calorie-dense. The hot dog pictured below illustrates both of these points. It’s been processed to remove quite a bit of water, plus it has a relatively high fat content. As a result, it’s more calorie-dense than the plain meats pictured.
Since most of these proteins are eaten cooked, I used the cooked weight and chose the corresponding USDA nutrition data for the food after cooking. For example:
USDA 15237 – Fish, salmon, Atlantic, farmed, cooked, dry heat
USDA 23476 – Beef, ground, 93% lean / 7% fat, crumbles, cooked, pan-browned
These entries take into account the water loss and subsequent increase in calorie density that typically occurs with specific types of cooking. They may not be quite as accurate as using raw weight with raw nutrition data, but they’re close enough that it’s not going to matter as long as you’re consistent in how you measure and you choose an entry which specifies “cooked,” plus the cooking method.
See this Google spreadsheet for more information.
2) Fruits and vegetables
Fruits and vegetables primarily contain carbohydrates, which provide 4 calories per gram. But not all carbohydrate-rich foods are created equal. The more fiber and water a carbohydrate-rich food contains, the more satiating it may be. For example, low-calorie fibrous vegetables are quite filling.
When comparing fruits and vegetables, fresh fruit tends to be more satisfying than dried fruit. The graphic below illustrates the difference in volume between a fresh fruit such as grapes and their dried counterparts, raisins.
Similarly, where vegetables are concerned, the ones with a higher water content, such as the spaghetti squash pictured below, will likely be more satisfying than an isocaloric amount of a drier and therefore more calorie-dense version, such as corn or peas.
3) Grains and Starches
Where grains and starches are concerned, water and fiber content contribute greatly to satiety as well. Starchy vegetables that contain a lot of water and fiber, such as potatoes and winter squash, tend to be quite satisfying. With grains, you may find that fiber and water-rich options, such as cooked oatmeal, are more filling than drier grains like bread, pasta or rice.
An additional factor that we can consider when discussing calorie density is how much air a food contains. Take rice cakes, for instance. Even though rice cakes can mathematically be classified as calorie-dense by weight alone, they are so full of air that they actually provide significantly more volume than their calorie density implies. As you can see below, a mere 26 grams of rice cakes provides a surprisingly large volume of food.
For the foods that are typically eaten cooked (like the pasta, rice, potatoes, squash, etc.) I took the cooked weight and used the corresponding USDA nutrition data for the food after cooking. For example:
USDA 11091 – Broccoli, cooked, boiled, drained, without salt
USDA 20121 – Pasta, cooked, enriched, without added salt
These values take into account the water loss and subsequent increase in calorie density that typically occurs with specific types of cooking. They may not be quite as accurate as using raw weight with raw nutrition data, but they’re surprisingly close in most cases, and they make measurements easier.
Although this may seem inconsistent, I did it this so as to compare each food in the state in which we’d most likely be eating it. This just gives a more realistic visual of the differences in volume.
See this Google spreadsheet for more information.
Fat provides 9 calories per gram, meaning that pure fats, such as oils, have the highest calorie density out there. Again, this doesn’t mean that fat is inherently good or bad. In fact, consuming enough dietary fat is important for health. Some people find fat to be very satiating. Personally, I don’t find that fat gives me as much satiety as protein or complex carbohydrates, but your mileage may vary.
Since fat provides just over double the calories per gram than proteins or carbohydrates, fatty foods make it easy to exceed your daily calorie budget before you know it. So enjoy some dietary fat, especially those from high-quality sources, but use moderation so that your total caloric intake stays in line with your goal.
Similar sources of fat provide roughly comparable calories. For example, different oils — such as olive oil, peanut oil and coconut oil — are similar in calories. Different nuts are also similar in calories to each other, but lower in total calories than oils.
This is because nuts don’t provide just fat. They also provide some carbohydrate and protein, which are both lower in calories per gram than pure fat. As a result, nuts have slightly fewer calories than pure fats such as oils. This mix of macronutrients is also why plant fat sources, such as olives and avocados, are even less calorie-dense than either nuts or oils.
5) Sweets and snack foods
Another factor that can affect calorie density, especially in the case sweets and snack foods, is how processed a food is. Not that there’s anything inherently wrong with processing food. Almost everything we eat has been processed to some extent.
But the more processed a food is, the less air, water and fiber it tends to contain. Additionally, fat is typically added, which is more calorie-dense than carbohydrate or protein alone. Therefore, the final product may be more calorie-dense than its constituents.
When looking at the popcorn in the graphic below, we can see another example of how air content affects food volume. Even though the popcorn is assigned a middle-of-the-road calorie density by weight, we can clearly see that it provides far more volume than anything else in the picture.
Wrapping Things Up
In summary, calorie density gives us a way to compare volume for the calories, or calories for volume, between different foods. If you’re dieting, reducing the calorie density of your diet will help you feel fuller for fewer calories. If you’re massing, increasing the calorie density of your diet will help you get more calories in without making you feel as full.
As you probably noticed from the pictures above, fruits and vegetables are generally the least calorie-dense foods, followed by protein and starches, then by fats and junk foods. You can use the calorie density hierarchy to design your own diet template based on your goals.
For example, if you’re dieting, you could make the least calorie-dense foods (e.g., fruits and vegetables) the foundation of your diet. Then add enough protein for your body weight and goals (with some wiggle room for preference), choosing higher-volume proteins if that’s what you want. Add enough starchy foods to fuel your training and to feel good (again, with some wiggle room for preference), choosing higher-volume starches if that’s what you want. And then add a little bit of fat.
If you’d like to learn more about the calorie density of the foods pictured here, please visit the spreadsheet with the full data. There you’ll find the total calories, grams of each macronutrient, calorie density, typical serving size, and calories per serving for each of the foods above. If you have any questions, please feel free to leave them in the comments.