Author Steve Siebold is causing a lot of controversy with his new book, “Die Fat or Get Tough.”

Siebold says it’s simple: if you’re fat, it’s your fault. He says being fit or being fat is simply a matter of mental toughness and personal responsibility. He also believes that doctors and patients alike overplay medical conditions as an excuse for people being overweight.

People spend millions of dollars each year on weight-loss products, including books, special diet foods and pills. But Siebold, who has taught mental toughness techniques to some of the country’s biggest and most successful companies, says there’s no mystery surrounding weight loss.

“You do the work, you get the results. You don’t do the work, you get fat,” he tells Growing Bolder.

Siebold says he’s not trying to offend or insult people. He just wants to be a wake-up call and inspire people to stop making excuses.

And he speaks from experience. Six years ago, he was 40 pounds overweight and he made all the same excuses himself. But then, he says he simply made a decision that he did not want to be overweight anymore and he started to act on it.

For his book, he interviewed 500 fit people and 500 fat people and discovered some significant differences in the ways those two groups think.

He highlights some ways you can start changing your thinking and reveals the first step you should take if you’re ready to change your life forever.