Health is a great blessing, but the moment you make health one of your main, direct objects you start becoming a crank and imagining there is something wrong with you. You are only likely to get health provided you want other things more—food, games, work, fun, open air.
 C. S. Lewis, Mere Christianity (1952). copy citation

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Author C. S. Lewis
Source Mere Christianity
Topic health food
Date 1952
Language English
Reference
Note Adapted from a series of BBC radio talks made between 1942 and 1944
Weblink https://www.dacc.edu/assets/pdfs/PCM/merechristianitylewis.pdf

Context

“It is since Christians have largely ceased to think of the other world that they have become so ineffective in this. Aim at Heaven and you will get earth ‘thrown in’: aim at earth and you will get neither. It seems a strange rule, but something like it can be seen at work in other matters. Health is a great blessing, but the moment you make health one of your main, direct objects you start becoming a crank and imagining there is something wrong with you. You are only likely to get health provided you want other things more—food, games, work, fun, open air. In the same way, we shall never save civilisation as long as civilisation is our main object. We must learn to want something else even more.
Most of us find it very difficult to want ‘Heaven’ at all—except in so far as ‘Heaven’ means meeting again our friends who have died.” source