Extreme muscle soreness from dairy?

[NFK]

Being a scientist I am aware that we tend to confuse correlation with causality. My assessment would be: I have tons of datapoints from years of problems, however, these are rather soft datapoints since I wasn't tracking my nutrition or my training.

I would say that the last few weeks constitute hard data points, but only a few in total of course: Training was following strict programming: Nutrition was tracked down to the smallest details (I track everything when I can, love the ability to also periodically check my micronutrients). Breakfast and lunch + snacks are the same every (week)day with slight deviations in portion sizes of the individual components. The only real difference over these weeks was greek yogurt with oats instead of milk with oats in the evenings to get a bit more protein in, which also indicates that lactose shouldn't be the problem, because greek yogurt is lower in lactose.

I am still very much interested in figuring this out, so the next logical step is to cut greek yogurt out of my diet for a few weeks and see what happens then. I might introduce it again afterwards just to see if it is reproducible or if I drew my conclusions too fast based on my previous experience.

Not too surprised you haven't heard of it, I tried a ton of google (and google scholar) searches before asking if anyone has ever experienced this, but didn't find anything, apart from a few "scientific" studies saying casein might reduce muscle soreness, to directly be countered by other studies that found it had no effect.

[Robert Santana]

Try cutting it out after you have a string of training sessions under your belt and do so mid week and not during your double rest. Very odd indeed