It appears here that all agree that gluttony is a sin. St. Benedict of Nursia, in his Rule for monastics, memorably stated:
St. Benedict, the Rule, Chapter 39: On the Measure of Food
Above all things, however,
over-indulgence must be avoided
and a monk must never be overtaken by indigestion;
for there is nothing so opposed to the Christian character
according to Our Lord's words,
"See to it that your hearts be not burdened
with over-indulgence" (Luke 21:34).
As it is established that gluttony is a sin for both the thin and the overweight, I would be very interested to know how people can become obese without indulging in gluttony. Is it possible? I understand that people have different metabolisms, but shouldn’t a person with a slow metabolism simply require less food than a person with a fast metabolism? It seems that many people still eat like farmers and yet live sedentary lifestyles, or they eat foods that are filled with calories and fat to please the taste buds but are devoid of nourishment. Consequently, there is today the phenomenon in the developed world of being “overfed and undernourished”.
St. John Cassian identified three forms of gluttony in his Institutes for monastics:
St. John Cassian, The Institutes, Book V, Chapter XXIII
For the nature of gluttony is threefold: first, there is that which forces us to anticipate the proper hour for a meal, next that which delights in stuffing the stomach, and gorging all kinds of food; thirdly, that which takes pleasure in more refined and delicate feasting. And so against it a monk should observe a threefold watch: first, he should wait till the proper time for breaking the fast; secondly, he should not give way to gorging; thirdly, he should be contented with any of the commoner sorts of food. For anything that is taken over and above what is customary and the common use of all, is branded by the ancient tradition of the fathers as defiled with the sin of vanity and glorying and ostentation.
These three forms of gluttony are no less applicable to the laity than to monastics, and by the definition given by St. John Cassian, in most cases both the overweight and the thin are often guilty of this sin. Since gluttony is a sin, we should not be quick to judge others because of their overweight condition, but should rather question ourselves to see whether we too are gluttonous despite our thin appearance, if indeed we are not overweight. Do we snack between meals or eat food that only appeals to the sense of taste but has no nutritional value? If so, then we are guilty of two out of the three forms of gluttony, even though we may not do so to excess, or even though such excess does not result in added weight on account of our metabolism or active lifestyle.
That being said, while we all struggle with gluttony in one form or another, I would still like to repeat my question above - is it possible to be overweight and even obese without gluttony? If a person begins to put on a multitude of excess pounds, are they not eating too much, too often, or foods that are only for taste and devoid of nutritional content? As St. Benedict acknowledges in his Rule, one measure of food is not equally sufficient for all, but rather will depend on a person’s age, health, the amount of physical labor, etc. If we put on excess weight, then, is this not a clear sign that we are consuming more than what our body needs, given our own unique characteristics and lifestyles, or that we are consuming foods that simply gratify the sense of taste but cannot be metabolized by the body?
By the way, the above link to St. John Cassian’s writings on gluttony may be very helpful if anyone is having a difficult time in this area.