A pet-peeve of sorts is accuracy in food labels. Today’s target? Lentils.
I. Lentils
My first encounter with lentils came back around 1993 or 1994. One of my math professors was Iranian and cooked a mean rice, chicken, and lentil dish with some saffron, etc.
In the following years I ate my share of Indian food, frequented a couple Nepali restaurants, and had all sorts of dal. But I did not prepare lentils that often myself.
That changed this year when I was looking for a good vegetarian protein source for Ms. S. (and myself), one that, like various beans, goes well with rice or other grains to form complete proteins. To my pleasant surprise lentils were a hit with Ms. S., who did not eat them on a regular basis at all, and since then the’ve become a staple of our pantry.
II. The Pros
We keep a supply of all sorts of dry legumes around, mainly beans (black, navy, kidney, black-eyed peas), peas (yellow and green), and lentils (usually green or brown, but I’ve picked up some red and french from bulk bins). Lentils are higher in protein than peas, and they’re lower in fat than some beans. They cook quickly (13-20 minutes, depending on how tender you want them) and do not need to be presoaked. They’re fine as a side on their own or with a grain, they go well, a bit cooled, in salads, they can make fritters a-la-falafel, and it’s easy to serve up a quick and tasty soup. That’s not even counting any of the more spiced, flavorful, and/or complex dishes that are out there.
III. The Issue(s)
Let’s consider the reported “nutrition facts” from various bags of dry lentils.
The Great Value (Walmart ‘brand’) has a serving size of 35g, giving 80 calories, no fat, 20g of carbs (11 fiber and 2 sugar), and 10g of protein.
The Market Pantry (Target ‘brand’) has a serving size of 1/4 cup (dry), or 32g, for 70 calories, with no fat, 19g of carbs (9 fiber and no sugar), and 8g of protein.
The Winn Dixie bag promises a 1/4 cup (dry), or 35g, serving for 120 calories, consisting of no fat, 20g of carbs (11 fiber and 2 sugar), and 10g of protein.
And finally the Publix bag is listed at 1/4 cup (dry), or 32g, 70 calories, no fat, 19g carbs (9 fiber and 0 sugar), with 8g of protein.
There is considerable consistency here if one adjusts for 32g or 35g servings (each listed as 1/4 cup … which means it depends on how you measure volume, so I just go by weight), though the Winn Dixie bag is a calorie outlier.
Let us look at what the ‘NutritionData’ tool at self.com provides. For a 1 cup, 192g, serving (dry) there are 678 calories, with 2g of fat, 115g of carbs (59 fiber and 4 sugar), and 50g of protein. If you ‘normalize’ that to, say, the 35g servings above, we get about 123 calories, negligible fat, 21 carbs (11 fiber, about 2 sugar), and about 9g of protein. This is consistent with the Winn Dixie bag. [ source ]
If I’m looking to count calories, then I want lentils to have either 70 or 80 calories per serving (depending on how I measure them), but when I see closer to 120 or 130 calories per serving, I’m actually seeing something more consistent with, say, black beans, which the same NutritionData utility tells me have about 95.5 calories per 28g (dry) serving (4/5 of 35), or about 120 per 35g. The protein is slightly higher (7.2 vs 6 per 28g) for the lentils vs. the beans, but the carb and fat content are about the same.
I’m not the only one who has wondered about which number is correct, but the ‘answers’ provided by other readers/users (see also: caloriecount.about.com and caloriecount.about.com, for example) come down to counting dry vs. cooked, cups vs. grams, and the like. And those ‘answers’ are obviously wrong. Sure, the person asking the question may be measuring incorrectly, too, but that’s not where the issue lies.
IV. Fiber
The nuisance-slash-pet-peeve is how fiber and carbs are counted. Lentils have both soluble and insoluble fiber. The soluble fiber, per its name, will interact with water to form a nice, gummy mucilage, etc., whereas the insoluble mostly adds to stool bulk. Lentils have mostly insoluble fiber, whereas other pulses have a more even mixture.
Along with that soluble fiber beans contain large sugars — oligosaccharides — that pass into the intestine undigested, where a number of bacteria are happy to munch of them, and produce short-chain fatty acids, which we do use-slash-‘burn’. Soluble fiber can be ‘fermented’ and contributes ‘usable calories’, whereas for the most part it appears that insoluble fiber does not. (See also: Dietary Fiber)
Of course I’m simplifying a bit.
In any case, the obvious answer as to why some bags of lentils give about 80 calories for 35g (dry) while others list 120-130 is that the latter count all the carbohydrates toward the lentils’ calories, whereas the the former count only the non-fiber carbs. If we take the Publix lentils, at 70 calories, the 8g of protein contribute 32 (at 4 calories per gram). We’ll ignore fat, which means we have 38 calories to account for, but the 19g of carbs should give us 76 calories on their own for a total of 108. On the other hand, if one only counts the non-fiber carbs, about 10g, then one is much closer (32 protein + ~40 carbs) to the 70 on the package. The Great Value at 80 calories has 40 from protein, and 20g of carbs (80 calories, for 120 total), but 9 non-fiber grams of carbs (so 40 + 36 calories, close to 80).
Since most of the fiber in lentils is insoluble and insoluble fiber does not really seem to contribute to usable calories, the 70 calorie and 80 calorie listings do not strike me as that misleading. And given how the numbers add up, it’s clear that the packaging is not counting grams of fiber toward the calories-per-serving. At the same time there’s both inconsistency and a lack of transparency about this that makes it frustrating. There is no clear labeling effort to tell me how the accounting is being done, and there is no clear standard by which manufacturers choose to label their products. I can’t calculate my daily calorie intake in any accurate fashion by adding up grams of protein, carbs, and fat and multiplying appropriately.
Of course some of this is a non-issue or just overblown. I’m not diabetic or similarly in need of counting my carb intake or caring about “net carbs.” And the nutrition “facts” we use and report are useful approximations at best, mostly just ideals, and to a great extent merely convenient and misleading fictions. Produce, in particular, will vary in nutrient content by season, ripeness, variety, and where it was grown. It’s a quixotic search for certainty when we either claim or wish to know that so many grams of organic item X contain this many calories and these amounts of specific micronutrients. And those items whose nutritional values we can most-accurately measure are those that have been most meticulously crafted with specific amounts of ingredients, that is: the overly-processed, pre-packaged items we’re all trying to avoid.
The Irony is Obvious
If you want to micromanage what you eat and feel certain about how many calories you’re getting, you need to eat crap; and if you want to eat “real food,” you have to give up some control.
It’s the type of uncertainty principle that Heisenberg might have appreciated.
