What does physical fitness have to do with spiritual fitness? The two might seem worlds apart, but J. Lee Grady, director of the Christian charitable organisation called The Mordecai Project, believes they're connected.

More than anyone else, Grady said Christians are the ones who have to make fitness a priority this 2017. "I won't win a popularity contest for saying this, but it's true: The American church is fat — and ministers are sometimes the biggest sinners when it comes to overeating," he wrote in an article for Charisma News.

"This may be one key reason we don't address bad eating habits from the pulpit. If a preacher is hiding his huge stomach with his Sunday jacket, he's certainly not going to deliver a sermon about gluttony," he added.

Grady then provided three important reasons why church people need to step up their fitness game. First, Christians should glorify God with their bodies.

"I know Christians who would love to go on a mission trip, participate in a three-day fast or lead a weekly discipleship group for teenagers. But they never do these things because they are limited by their physical abilities," he said. "Some of us are simply too overweight, too tired or too out of shape to engage in any type of rigorous ministry."

Next, Grady said people's control of their appetites affects every other area of their lives. Part of the fruit of the Holy Spirit is self-control, so Christians need to learn how to avoid overeating and select healthy dishes to consume. At the same time, Christians who indulge in gluttony might find themselves falling into the trap of addiction, adultery, or even gambling.

"Jacob's brother, Esau, sold his birthright for a bowl of stew because his appetite controlled his judgment. Many Christians have done the same. We forfeit certain spiritual blessings simply because we can't say no to food," he said.

And lastly, Christians need to keep fit in order to live a long and fruitful life. Grady said it is a lie that people can no longer be fit once they reach their 50s or 60s, because biblical character Caleb was as strong at the age of 85 as he was at 40.

"God has promised the righteous a long life, but that isn't an automatic guarantee. Long life requires wisdom, which includes healthy eating, regular exercise, proper rest and stress management," said Grady.

If people constantly binge on pizzas, sodas, and processed sugar, they shouldn't find themselves surprised if they end up with heart ailments, high blood pressure, or diabetes. So instead of eating for the moment, Grady suggested that people always keep tomorrow in mind when they are looking at the menu.