Overindulgence in food or drinks may seem like an ordinary thing that's not worth truly getting worried about. But in truth, it is not something that should easily be dismissed.

In fact, gluttony is one of the seven deadly sins in Christian tradition, the other six being envy, greed or avarice, lust, pride, sloth, and wrath.

Why is it considered a grave sin to overeat?

It's because "the physical affects the spiritual," according to Pastor Shane Idleman of Westside Christian Fellowship in Lancaster, California, as reported by Faithwire.

In a New Year's Day sermon titled, "A Prisoner of Appetite: Is Unhealthy Eating a Sin?", Idleman pointed out that there's an intricate link between physical and spiritual health.

In urging his parishioners to start eating healthy, the pastor said Christians must be mindful not only about what they watch and listen to, but also about what they put inside their bodies.

He defined eating "unhealthy" as the act done by people who have the ability to take care of their body but deliberately choose not to. He said this is something that "grieves the Holy Spirit" and is tantamount to "disobedience" to God.

Idleman said there is an urgent need to tackle this subject because "the modern American lifestyle promotes gluttony." He believes healthy eating is one of the essential issues that Christians need to discuss.

The pastor's message resonated well with his flock, having delivered it on the first day of the year when people start making their "resolutions."

Idleman admitted that he, too, once struggled with bad eating habits and that he only realised the gravity of the problem not too long ago. "This time last year I was probably 240 pounds," he said. "It's always been a struggle since I was a little boy."

"When I'm overweight it's because of neglect in this area," he said. "And it's hard to preach on what you're not 'living out.'"