I was actually a bit surprised by the low regression coefficient values in figure 3. To me, the low values say that many of those features are not hugely important. The authors don’t emphasize this, but they also found that going to sleep later correlated with higher morning alertness.

My own takeaway from the data is a bit different from what the authors say conversationally (vs in the figures). I’d summarize the paper, mostly based on figure 5b, as:

Try to be happy, old, sleep well, and don’t eat too frequently.

In terms of breakfast, the data’s main conclusions are to avoid a lot of sugar (which is hugely important), and to wait a while before eating breakfast (see fig 3).