Nutrient Density Part 2:  Incorporating Nutrient Density into your Diet

In Part 1 of this article we learned what nutrient density is, how it’s measured and the different systems used to do so. We also learned that the champions of nutrient density are fresh vegetables with fresh fruit coming in second place. We already knew that we needed to include more fruit and vegetables in our diet and understanding nutrient density was the confirmation as to why. However, simply stopping at “Eat more fruit and veg” would be a terrible waste of the potential of nutrient density to improve our diets.    

One thing that many of the studies on nutrient density found is that foods that are nutrient-dense tend to be calorie-poor and vice-versa; energy dense foods tend to be nutrient poor {1,2}. This is logical considering nutrient density is a measure of nutrients per calorie. In fact high levels of fat or sugar are usually enough to significantly reduce the nutrient density of many mixed food meals (this will be important later).

However, as we said in Part 1 of this article, we all have a daily calorie budget that we need to stick to. In other words, we need to eat a certain amount of calories every day in order to, you know... live. Getting all of these calories from nutrient-dense foods that are low in calories is no mean feat. Below, I’ve included a list comparing the nutrient contents of seven very nutrient-dense vegetables. Take a look first and we’ll make some important observations later.

Have you taken a look? Great, now let’s take note of some important points.

Firstly, these are all clearly very nutrient dense foods. A 100 kcal portion provides decent quantities of a wide range of vitamins, minerals etc. That’s a definite thumbs-up.

However, now take a look at the weight of each of those 100 kcal portions. A 100 kcal portion of fresh spinach weighs almost half a kilogram. In fact, the total weight of a 100 kcal portion of all those vegetables combined is almost 2.4 Kg. That is a lot of vegetables for just 700 kcal. This is mostly due to the natural water content of the foods. High-nutrient density foods (like vegetables) tend to have a high water content and low nutrient density foods (sugar, some cereals etc.) have lower water contents.

Now, one advantage here is that these calorically poor, nutrient dense foods add a lot of physical bulk to your diet. This improves satiety (helps you feel full and satisfied), which can help with diet adherence. However, getting enough calories exclusively from these foods would be a pain in the ass (quite literally based on their high fiber content). If you consider that the average male needs about 2500 kcal/day to maintain weight (remember Bobby?), then a person would need to consume over 8.5kg of fresh produce (based on the values below) just to maintain weight. That’s a lot of chewing and I doubt even the most hardened raw-food vegan would be willing endure that every day.

It’s worth pointing out that in the majority of nutrient density scoring systems, the cream of the crop when it comes to nutrient-rich foods are green leafy vegetables (spinach, kale, bok choy, lettuce etc.) followed by dark orange/red vegetables (turnips, squash, carrots, bell peppers etc.). Dark colors in fruit and veg are often associated with a greater concentration of plant pigments, many of which have been shown to have health benefits {3}. Accordingly, you should try and include as many of these dark green leafy vegetables and dark colored orange/red vegetables in your daily diet as possible.

So it would appear that in order to meet our daily caloric requirements, we need to ingest more calories (in the form of carbohydrates and fats) from energy-dense foods that are “LESS” nutrient-dense than the foods in the table above. I say “less” nutrient-dense because thanks to an understanding of nutrient density, we can make more informed decisions about the energy dense foods that we consume, choosing more nutrient-dense options when we can.

To do this we’ll take a look at how the nutrient density of similar foods varies and also, how nutrient density is affected by a foods energy content (which can be altered by different forms of food processing).

Nutrient density goes down when energy density goes up because energy sources themselves are devoid of nutrients. The table below shows the nutrient content of 100 kcal portions of both sugar and oil. It’s clear that they don’t provide any thing else other than calories. This is why added sugar and fat are often considered “Empty Calories” as they provide energy without nutrients.

While olive oil does provide monounsaturated fats, anti-oxidants and polyphenols and has been shown to have health benefits {4}, for the purpose of this example we will use it here simply as an example of fats in general and their effect on nutrient density.

It now becomes quite clear why a lot of processed foods that are high in added fats and sugars (such as cakes, cookies, desserts etc.) have negative NRF9.3 values (very low nutrient densities) {5}.

Now let’s see how that extra energy content can affect your choices of other, otherwise similar foods. Below is a table comparing samples of three different foods; beef, yogurt and cheese, that differ only in their fat contents. Take a look at the table and take note of the differences between the lower-fat (green) and higher-fat (red) options. For anyone curious, the lean beef example is an “eye of round” steak cut, one of the leanest cuts of beef available and a great high-protein, low-fat choice.

The first thing you’ll notice is that the nutrient density (nutrients per calorie) of the lower-fat foods is (significantly) higher than their higher-fat counterparts. You’ll also notice that the weight (portion size) of the lower-fat version is more than the higher-fat version. While not shown here, lean poultry, fish and seafood in general give even better values than lean beef (something we probably knew already).

In practical terms, this means that in order to maximize nutrient density from a certain food, choosing lower fat versions is a particularly good strategy, especially if your caloric budget is low. I’m not saying this to demonize fat (fat is essential for good health and should be maintained at adequate levels) but I want to make it clear that sometimes choosing lower-fat options is a good policy. On top of that, as lower fat options tend to provide more food volume for the same calories, this can greatly improve the satiety value (feeling of fullness) of meals containing these foods.

Next, let’s take a look at the differences between grains that are left in their whole, unprocessed state and their refined counterparts. As examples, we will look at the two of the most commonly consumed grains in the western diet; wheat and rice in their wholegrain and refined forms, along with oats, and two varieties of legumes for comparison.

Once again, we can see that the nutrient content of the wholegrain version (green) is greater than that of its refined counterpart (red) in the wheat and rice samples. This is to be expected considering the germ and bran of grains (the part removed in the refining process) are particularly high in vitamins, minerals and fiber. This could be amongst the reasons that diets high in whole grains have been shown to reduce the risk of coronary heart disease, stroke {6-8}, type 2 diabetes {9} and colon cancer {10}. Long story short, eat more wholegrain cereals.

However, if you look at the cereals/legumes in the blue columns you can see that it might actually be a smart move to replace some of the more conventional cereal grains (wheat and rice) with grains like oats or legumes like chickpeas or lentils etc. One of the main areas where these foods generally surpass wheat and rice is in mineral and especially, protein content. The protein content is particularly useful as achieving adequate protein can sometimes be difficult on reduced calorie diets. In such a case it makes sense to replace (at least some of) your daily grains (pasta, rice etc.) or other carbohydrates such as potatoes with legumes (peas, beans etc.), which give a greater contribution to your daily protein needs.

None of the currently available nutrient density scoring systems are perfect and if used incorrectly could even result in diets ridiculously low in total calories and protein just because of the volume that vegetables take up.

If you look at the NRF9.3 or ANDI food tables online you’ll see that they are dominated by low calorie, dark green, leafy and other vegetables. Lean meats and fish, low-fat dairy, whole grains and legumes pale in comparison. However, while vitamins and minerals are incredibly important for a healthy diet, so too is adequate calorie and macronutrient consumption. This is where the aforementioned less nutrient dense, high energy density meat/fish/dairy/grains/legumes etc. play an essential role in a balanced diet.

Learning about nutrient density makes choosing from these options a more informed decision so that you can more wisely spend your calorie budget. As a final note, it’s important to point out that no single food can provide you with all the macro and micronutrients that you need to be healthy. With this in mind, always remember that a varied diet, with nutrients coming from a wide selection of vegetables, fruit, grains, legumes, dairy, meat, seafood etc., is the easiest way to ensure a well-balanced, nutrient-rich diet.

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Bibliography

1. Darmon N, Darmon M, Maillot M, Drewnowski A. A nutrient density standard for vegetables and fruits: Nutrients per calorie and nutrients per unit cost. J Am Diet Assoc. 2005;105(12):1881–7.
2. Drewnowski A. Concept of a nutritious food: Toward a nutrient density score. American Journal of Clinical Nutrition. 2005. p. 721–32.
3. Manach C, Scalbert A, Morand C, Rémésy C, Jiménez L. Polyphenols: Food sources and bioavailability. American Journal of Clinical Nutrition. 2004. p. 727–47.
4. Estruch R, Ros E, Salas-Salvadó J, Covas M-I, Corella D, Arós F, et al. Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med 2013;368(14):1279–90.
5. Drewnowski A. The nutrient rich foods index helps to identify healthy, affordable foods. Am J Clin Nutr. 2010;91(4).
6. Flight I, Clifton P. Cereal grains and legumes in the prevention of coronary heart disease and stroke: a review of the literature. Eur J Clin Nutr. 2006;60(10):1145–59.
7. Liu S, Stampfer MJ, Hu FB, Giovannucci E, Rimm E, Manson JE, et al. Whole-grain consumption and risk of coronary heart disease: results from the Nurses’ Health Study. Am J Clin Nutr. 1999;70(3):412–9.  
8. Jensen MK, Koh-Banerjee P, Hu FB, Franz M, Sampson L, Grønbœk M, et al. Intakes of whole grains, bran, and germ and the risk of coronary heart disease in men. Am J Clin Nutr. 2004;80(6):1492–9.
9. Aune D, Norat T, Romundstad P, Vatten LJ. Whole grain and refined grain consumption and the risk of type 2 diabetes: A systematic review and dose-response meta-analysis of cohort studies. European Journal of Epidemiology. 2013. p. 845–58.
10. Aune D, Chan DSM, Lau R, Vieira R, Greenwood DC, Kampman E, et al. Dietary fibre, whole grains, and risk of colorectal cancer: systematic review and dose-response meta-analysis of prospective studies. Bmj. 2011;343(November):d6617–d6617.