Has anyone ever reported feeling like they were more likely to catch a cold upon first starting a low carb/primal type diet? (not strictly Paleo)

My dh and I went Primal just over 2 weeks ago and he got a bad cold about a week in.

I didn't get it though, but thought it could be a kind of detox. Or maybe as you say lowered immune response.

It's normal. It's called the low carb flu. Mine was rough for a day, a pain for another, and lingered in the background for a week. Some don't experience it. Some simply cannot handle it and go back on carbs.

I've seen it explained as your body transitioning from burning sugar (glucose) for fuel to burning fat (ketones). Before the switch is complete you get weak and feel ill from a lack of fuel burning.

I've also heard it explained that certain gut flora that thrive on sugar and grains protest, make you sick, then die and part via your stool.