I'm not certain that his response was an emotional one, but a fact-based one. Controlled, educated, fasting is excellent for those with blood sugar/ a1c / insulin/ cortisol issues which most people over 50 have some problem with. It's real and it can stop you from losing.

Now, he has doctors who are experts in dieting and fasting as a healing method that happens to help you lose a few pounds, but for the average person who has no issues, it's a firehose where a squirt gun is needed.

So I'm in agreement that care should be taken, but his reasoning may have been more about the fact that in the past he had exhausted other alternatives and found this effective.