How much exercise will lower chronic disease risk?

That is interesting because there is a viral video by a doctor who draws who recommends 30 minutes walking a day (30 2 7) or 42 MET minutes per week. https://youtu.be/aUaInS6HIGo?t=4m42s At the 4:42 mark he says, "More activity better but the rate of return seems to decline after 20 or 30 minutes." I did not believe the doctor so much, but I believe this study. Of course, a little is a lot better than none.

Walking would seem to also be good for digestion, helping food to pass through the digestive track.