I agree with his central point, that it can take some time to get back working on a project (whether data analysis, programming, or writing), and so blocks of less than a couple of hours can be inefficient. Meetings that break up a work day can really erode one’s productivity: academics often spend too much time meeting and not enough actually working, and three hour-long meetings spaced evenly throughout the day can mean that you don’t get anything real done in the other five hours.
For me, the “ramp up” time for a project is less about re-familiarizing myself with the data files (though that can be true if I’ve not kept them well organized) and is more about the procrastination barrier (ie, inertia) and not keeping a good record of small chunks of work to tackle.
So, in addition to Rafa’s comment, that it’s best to pack meetings onto the same day (and I’m particularly happy when multiple meetings get scheduled at the same time, so I only have to go to one of them), I would add
Keep files organized and documented (so you don’t have to spend much time figuring out where things are)
Keep a “to do” list that is split into small chunks (like, “do this, than that, than that, than that”) rather than as whole projects (“work on project X”)
There’s a dual issue: many of my colleagues (wherever I’ve been):
Don’t show up for meetings
Don’t show up for seminars
Don’t volunteer to meet or share a meal with visiting seminar speakers
It’s important to protect one’s time and actually get things done, but you shouldn’t hide in your office with your door closed all week.
One last point: I’m surprised that Rafa hadn’t mentioned his idea of having all meetings done with everyone standing (rather than sitting), to ensure that meetings are kept as short as possible (don’t let anyone relax). You might extend that idea further and insist on some sort of stress position.