What do a couple of physicians know about climate change and sustainability?

As it turns out, rather a lot. We have distilled a very simple message that is well supported: Health is a major ecological issue — we need to exercise more, to eat better and we need to urgently engage with climate change and other sustainability challenges — and we all can participate to make a difference.

So, what is Globesity? Globesity is a term used by the World Health Organization (WHO) to describe the relationship that currently operates between personal fitness, national health systems and global sustainability. Basic laws of economics dictate that societies must choose where they allocate their resources — the classic economists’ analogy is "guns or butter", and we have similar choices to make regarding sustainability.

We do not, for instance, have the ability to deal with major ecological problems like global warming and prop up a health system overburdened by inactivity and poor food habits. People must learn to look after themselves, to exercise more and eat better.

In the big picture, sustainability starts with our own bodies. The Optimal Health Program presents a three-part blueprint for:

1. Creating a successful fitness lifestyle.

2. Eating in a way that will transform our health and that of the planet, and

3. Becoming eco-friendly in all aspects of our lives.

Fit body first; fit planet next. In our upcoming book we state, "While we deal with the larger ecological issues in part three, the whole of part one is devoted simply to the most powerful strategies we know for getting yourself enjoyably active, and part two to dietary tactics for weight loss and for improving your health. We’ll show you how starting in our own backyards, we can make a huge contribution to global sustainability in ways that can actually improve your life and be a lot of fun.

The reason for writing the book, a major commitment for an extremely busy couple, is passion and concern. "We’ve been concerned about the worsening health of society for a long time. The mission of our companies has always been to improve peoples’ lives. But like most people, we’ve started to get concerned about the bigger picture more recently.

The consequences of global warming are becoming obvious, even to the most intransigent of skeptics. Al Gore’s documentary An Inconvenient Truth has opened many eyes in this area and books like The Weathermakers by Tim Flannery and Heat by George Monbiot go a step further in spelling the issue out.

Scientists like Jared Diamond and Tim Flannery have also brought the challenges to broader sustainability into the spotlight through their books Collapse, by the former and The Future Eaters and The Eternal Frontier, by the latter.