Steve Siebold doesn’t think he is the most hated man in America, but his stance on obesity has generated pushback that ranges from disdain to death threats. His message is simple, but not popular: Obesity is not a disease, it is a choice and there are things you can do to change it.

Like work on changing your mind in order to change your body.

The process won’t be easy, and it won’t be fun, but when all else has failed, it just might work. The author of Die Fat or Get Tough: 101 Differences in Thinking Between Fat People and Fit People and Sex, Politics and Religion: How Delusional Thinking is Destroying America, Siebold does not want you to accept your body as it is, and he doesn’t believe you have to.

Siebold’s ebook Fat Loser! provides a set of strategies to address the underlying reasons diets fail. “This is psychological training,” Siebold said in a phone interview. In other words: it’s not the diets that fail, it’s the people.

“This is about personal responsibility. No one is coming to the rescue.”

The title is meant to be provocative, but not cruel. “It’s a play on words. A fat loser loses fat. I’ve lost fat. It’s meant to jolt people, to grab their attention.”

He’s mad as hell about the movement to normalize “fat,” in part because he believes people are not facing facts.

The recent announcement that fat-positive groups are lobbying for a fat Barbie is driving him crazy.

“All we are doing is saying it’s OK to have diabetes, heart disease and eat yourself to death. It’s giving up on the problem because people are afraid to face the truth.”

The book promotes “mental toughness” and strategies to make weight loss, as difficult as it is, more alluring than staying fat. And yes, he uses the word “fat” liberally. He ices the cake with it. Stuffs the goose with it.

The dropout rate for the free course he offers online at fatloser.com is about 50 per cent, he says. If you’re emotionally fragile, you may not get the humour of a guy on your computer screen talking “tubby” to you.

His message is about personal responsibility. Siebold, a former pro tennis player who blogs for The Huffington Post and works as a corporate motivational coach, says that after packing on about 40 pounds several years back he decided to look at the psychology of “fat” and “fit” people and see if his techniques for success in business could work for something as personal as changing your body.

The key is not which program you are on, Siebold says. Count calories, points, carbohydrates, he doesn’t care, as long as it’s reasonable and doctor approved. He’s not a nutritionist, but says he studied the habits and thought patterns of 500 fat and 500 fit people.

“Fat people eat for pleasure, fit people eat for health,” Siebold says. So you have to change how you get your pleasure, and train yourself to get pleasure from eating for something else: for vibrant health, for better sex, for more money.”

With a little effort, he says, over time you can build new mental habits.

Siebold says step one is to admit you are responsible for your weight and make a decision to change it. “You have to make a decision that you are going to do it. Without the decision, any diet is worthless.”