Homemade Yogurt — Caloric Conundrum

drooJohnson

So, I have a problem.

I made yogurt, thinking it might save me a few dollars. But now I'm realizing after probably 4-5 days of trying to do the math, there is no easy/good/reliable way to calculate the calories or macros for homemade yogurt.

Here's why I believe this.

I made yogurt from 2% milk. 2% milk has ~50 calories per 100g, and 3g protein. Acid Whey, which is the whey you get when straining yogurt, has ~24 calories per 100g, and ~1g protein.

You'd think I could just take the calories and protein from the volume of milk I started with — Let's just say 1000g for example — and subtract the calories and protein from the amount of whey I removed and weighed during straining — Let's say 600g — and I would have the final calorie and protein numbers for the strained yogurt.

Using our example numbers, we would start with 500 calories and 30g protein from the 1000g 2% milk. We would drain off 600g of whey, removing 144 calories and 6g protein. This would leave us with 400g of 2% Greek Yogurt, with 356 calories, and 24g protein.

A normal serving of 2% Greek Yogurt, according to my brand-of-choice Fage, is 200g. So, a serving of our homemade 2% Greek Yogurt would be 178 calories with 12g protein.

Here's where I ran into trouble.

2% Fage comes in 200g tubs. Each tub has 150 calories, and 20g protein. The ingredients don't list anything but the dairy, and the live cultures they add to ferment that dairy. For every gram of protein in 2% Fage, there are 7.5 calories. Our homemade version has almost double that, at ~14.75 calories per gram of protein.

Here's where it gets really tricky.

The number of calories per gram of protein goes down as you remove whey. So just remove more whey, right?
Actually, no. Even if you removed 1000g of whey from 1000g of 2% milk, you STILL wouldn't match Fage's calorie-to-protein ratio. 1000g of whey has 240 calories and 10g protein. Subtracting that from our 1000g of 2% milk ( 500 calories, 30g protein ) results in 260 calories, and 20g protein. That's 13 calories per gram of protein...

It also isn't possible to remove 1000g of whey from 1000g of milk, but given the information we have about protein and calories in whey and milk, that shows us the lowest calories-to-protein ratio that could ever be theoretically possible.

So, my questions are these...

How are we supposed to calculate this stuff?
Has anyone ever done an accurate nutritional analysis on 2% yogurt by itself with no additives and no whey strained out?
Does milk completely switch up its macros when we ferment it, even if it doesn't lose mass?
Are Fage's nutritional facts incorrect?

kirstenb13

I think it's most likely that Fage is allowed to label its product as only containing milk but is actually assembling it from milk that has been separated before, so they add protein or fat back in at the ratios they want. As far as I know the milk fat is removed for all commercial dairy products (even the regular milk) and then added back in so it can be at 2 or whatever percent. So no way to replicate that at home.

ahoy_m8

Do the bacteria consume lactose/sugar, thereby lowering carbs (sugars) and corresponding calories in the process?
How would you feel about just logging the homemade as Fage? Not exact, but probably close? Close enough?

drooJohnson

I'd be okay with the inaccuracy, though this seems like something that shouldn't be so difficult to figure out. I keep to a decently strict macro breakdown, trying to keep it as close as I feasibly can to ⅓ carbs, ⅓ fats, and ⅓ protein, as it has been shown to help with AD/HD symptoms, and for some people it's even helpful enough that they can lower their dosage of medication without sacrificing efficacy. Along with this I do regular strength training, for the same reason. Coming in too low on my protein could screw with some of this.

But, I suppose I can deal with that once it becomes a problem, and just remember to keep an eye on it, right?

Still, just because I'm an inherently curious soul, I really would love to know if there is a way to do this accurately. The chemistry of this whole process fascinates me, and as an avid baker, there's no substitute for precision.

powered85

I make a ton of homemade Greek yogurt. I too have been trying to figure out this calorie discrepancy especially around why commercial products have WAY more protein http://community.myfitnesspal.com/en/discussion/10442397/issue-w-homemade-greek-yogurt-nutritional-calculation-why-a-lot-different-than-commercially-made#latest

I've ran my numbers several times and I believe I'm calculating my recipe correctly. Something is either missing in the scientific conversion process around the protein content or companies are adding more yogurt.

I strain mine super thick (I use 2% usually) to the point it's almost like cream cheese. So you'd think it'd be very dense with protein.

A 250g serving of mine comes out to around 13g protein. Most commercial 2% a 250g serving packs 25g+. Carbs and fat are off by only 1-3g in comparison.

powered85

kirstenb13 wrote: »

I think it's most likely that Fage is allowed to label its product as only containing milk but is actually assembling it from milk that has been separated before, so they add protein or fat back in at the ratios they want. As far as I know the milk fat is removed for all commercial dairy products (even the regular milk) and then added back in so it can be at 2 or whatever percent. So no way to replicate that at home.

I wonder if this is what's going on. Perhaps the food labelling guidelines allow for this?

ahoy_m8 wrote: »

Do the bacteria consume lactose/sugar, thereby lowering carbs (sugars) and corresponding calories in the process?
How would you feel about just logging the homemade as Fage? Not exact, but probably close? Close enough?

Believe the bacteria do consume sugars but not sure on how much. Considering that my homemade is close to commercial carb content I wonder if it's a fairly low consumption.

vingogly

I think you're overthinking things. There are inaccuracies in labels, and your bathroom and kitchen scales are not 100% accurate. Yogurt is a relatively small part of your diet so if you don't nail the nutritional info exactly, it's not going to make that much difference in the scheme of things.

powered85

vingogly wrote: »

I think you're overthinking things. There are inaccuracies in labels, and your bathroom and kitchen scales are not 100% accurate. Yogurt is a relatively small part of your diet so if you don't nail the nutritional info exactly, it's not going to make that much difference in the scheme of things.

Probably. But it's actually a big part of my diet as I eat a lot yogurt. I'm more interested in scientifically why the difference vs how many actual calories/g of protein is different. Calories are close it's the protein that seems to be way off.

powered85

So after some digging I stumbled upon this document http://www.dairyfoods.com/ext/resources/White_Papers/Greek_Yogurt-White_Paper-Final.pdf

Seems there is some commercial processes that can filter/concentrate the milk well beyond my capabilities at home to up the protein content of the yogurt. So this appears to explain why protein doesn't come out near as high making it at home.

HeidiCooksSupper

When I was straining non-fat regular yogurt to get Greek-style yogurt, I just used the figures from the USDA's National Nutrient Database for Standard Reference -- which is also the basic source food manufacturers use to determine calories, macros, etc. As they say, "close enough for government work."

Basic Report: 01256, Yogurt, Greek, plain, nonfat https://ndb.nal.usda.gov/ndb/foods/show/216?fgcd=&manu=&lfacet=&format=&count=&max=50&offset=&sort=default&order=asc&qlookup=yogurt+greek+nonfat&ds=Standard+Reference

Basic Report: 01114, Whey, sweet, fluid https://ndb.nal.usda.gov/ndb/foods/show/103?fgcd=&manu=&lfacet=&format=&count=&max=50&offset=&sort=default&order=asc&qlookup=whey&ds=Standard+Reference

powered85

HeidiCooksSupper wrote: »

When I was straining non-fat regular yogurt to get Greek-style yogurt, I just used the figures from the USDA's National Nutrient Database for Standard Reference -- which is also the basic source food manufacturers use to determine calories, macros, etc. As they say, "close enough for government work."

I was running my numbers against a commercial brand as well. When I started doing the math from the milk and subtracting the whey, that's when I became suspect that the protein was way off.

I don't think we can get close to commercial Greek protein content due to how they process the milk before/during production.

Although strained extremely thick, mine still compares more to regular yogurt for calories/carbs/protein and fat.

And also, if you use all 2% milk and strain the whey out, your mf% goes up as your final product is a lot more dense and there's basically no fat strained out in whey. My 2% Yogurt is actually around 4.4%. Delicious.