Best-selling author Dr. Ian K. Smith is world-renowned for his medical and diet advice. He is the expert and host of VH1's 'Celebrity Fit Club.' And in 2008, he created the Million Pound Challenge, a free national weight-loss initiative.

Now, he is helping people in another pursuit: the pursuit of happiness. In his new book, 'Happy: Simple Steps to Get the Most Out of Life,' Smith explores the human psyche from a scientific perspective to determine how happiness can be achieved. Surprisingly, it's simple, he said. It is connected to spending time with family, community involvement, doing good deeds and other uncomplicated steps.

Smith recently sat down with BV on Books to talk about happiness:

BV: Why did you decide to write this book?
Dr. Ian K. Smith: I was looking around and noticed that so many people were depressed or in a blue mood because of the recession, home foreclosures, the two wars, and rising unemployment. People were just down and out. I wanted to figure out what science had to say about happiness and how we can restore it. Are there things we can do despite the difficulties around us to boost our happiness? The good news is yes. You can improve your happiness. Fifty percent of your happiness is genetic, but you can control 40 percent of it. That is the focus of the book.

BV: What is the 40 percent that people can control?

IS: They are the things that are meaningful, engaging and purposeful, such as spending time with family or friends and doing good deeds for other people. These things require time, and our time is imbalanced these days, which has made it difficult to do things that bring happiness. The book teaches people how to reallocate their time and restore balance.

BV: If you are stressed out, do you have time to spend with friends and family? Are you at liberty to help others? And if you are broke, how are you going to do all of those things?

IS: Those all are good questions. There are things that require very little time. For example, if you are stressed out, sitting down and taking just 10 minutes to write a thank you letter to someone, not a text or an e-mail, is something that has been shown by scientific studies to boost your happiness by up to six months. Writing three things that you're grateful for at the end of the day also is a happiness booster. For example, you can write that you are grateful for getting home safely, that your parents are still alive or that the weather is good. There are many things to do that don't require time. What they require is a willingness to sit there and do it. Scientific studies show that these things are small but significant and attainable.

Dr. Ian K. Smith: I was looking around and noticed that so many people were depressed or in a blue mood because of the recession, home foreclosures, the two wars, and rising unemployment. People were just down and out. I wanted to figure out what science had to say about happiness and how we can restore it. Are there things we can do despite the difficulties around us to boost our happiness? The good news is yes. You can improve your happiness. Fifty percent of your happiness is genetic, but you can control 40 percent of it. That is the focus of the book. They are the things that are meaningful, engaging and purposeful, such as spending time with family or friends and doing good deeds for other people. These things require time, and our time is imbalanced these days, which has made it difficult to do things that bring happiness. The book teaches people how to reallocate their time and restore balance. Those all are good questions. There are things that require very little time. For example, if you are stressed out, sitting down and taking just 10 minutes to write a thank you letter to someone, not a text or an e-mail, is something that has been shown by scientific studies to boost your happiness by up to six months. Writing three things that you're grateful for at the end of the day also is a happiness booster. For example, you can write that you are grateful for getting home safely, that your parents are still alive or that the weather is good. There are many things to do that don't require time. What they require is a willingness to sit there and do it. Scientific studies show that these things are small but significant and attainable.

BV: Are you happy?

IS: Very. I've always been happy. I have optimism because I come from a family where we were very big in love and very poor in material goods. My grandmother taught me to see the patch of blue between the clouds. A lot of it has been about my attitude and my perspective. What I try to teach people in the chapter on optimism is that attitude can make all the difference.

BV: How does your advice differ from the Dali Lama in 'The Art of Happiness' by Howard C. Cutler?

IS: These things are on the same continuum. It's not like one book is radically different from the other. His is probably more spiritual than mine. However, I do mention in the happiness booster section that research has shown that spirituality is one way to improve happiness. My book is designed to do two things: Empower people to let them know that happiness is attainable, and to provide simple exercises to demonstrate ways to attain happiness.

BV: Most of your work involves diet and exercise. Does weight affect happiness?

IS: A lot of people who struggle with weight issues are people who are sometimes unhappy in their lives for one reason or another. One way of coping is emotional eating, or mindless eating. Sometimes losing weight will help people recover from their blue mood. However there is more to it than just losing weight. It's also about realizing they can't attach their happiness to external factors. Their happiness is not determined by whether they are accepted or rejected by outside people, but whether they love themselves, like where they are in their lives and whether they are doing things that are meaningful and engaging.

BV: What would you like readers to take away from the book?

IS: I would like people to walk away from this book with the feeling that, yes, happiness is attainable even in the most difficult of circumstances. Achieving it is inexpensive, simple and rewarding.