The authors did test the combination. HC or HF alone leads to less inflammation than HCHF. Note that the control diet for all of the experiments is chow, which is HCLF.

Hmm it’s odd. They did feed them chow, but the chow diet was significantly fewer calories than the HCHF or LCHF diets so it can’t really be compared with them. In fact they didn’t control for calorie intake so for all it’s known the higher calorie consumption of HCHF could be the cause.

According to the results section they also did not evaluate the hyperthalmic microglial activities of the Chow (HCLF) diet so it’s unknown from the paper if If the high carb only diet had detrimental results.

Wish I could ask the authors about these holes.

I agree with your concerns. I am also concerned that the chow diet (HCLF) does not provide the same type of carbs (wheat and corn) as the other diets tested (sucrose or starch).

I can't weigh in on the study design, but since the actual conclusion is much more conservative, we've gone with a representative phrase from it:

> Combined overconsumption of fat and sugar, but not the overconsumption of fat per se, leads to excessive CML production in hypothalamic neurons, which, in turn, stimulates hypothalamic inflammatory responses such as microgliosis and eventually leads to neuronal dysfunction in the control of energy metabolism.

You missed the critical part: "in rats".