You've seen them – those lean and lanky, fit people who credit their ability to maintain that look to eating moderate amounts of a well-balanced diet combined with a moderate amount of exercise.

They're the people who can eat a few bites of the yummiest dishes and say they've had enough. It's a trick I've yet to learn.

I like to run marathons, so moderation is something that doesn't come naturally to me. I put in a lot of kilometres in training – last week, almost 110. That's good and bad. I'm burning a lot of calories, but also developing a substantial appetite.

Think Michael Phelps – the diet, not the bong.

That doesn't do much good if you want to lose weight. You take in as much as you burn and your weight won't budge. You're also courting dietary disaster if you cut your activity but remain – as my father used to say – "a good eater."

A lot of the folks noted as experts in the fields of diet, nutrition, exercise and how the body works say we should emulate those mostly lean and lanky people and combine a moderate diet (a little over 2,000 calories for the average woman and a little over 2,500 calories for the average man) with moderate amounts of exercise – about 30 minutes, five times a week.

But what do they mean by "moderate exercise?"

Researchers at the School of Exercise and Nutritional Sciences of San Diego State University, think they have the answer: 3,000 steps over 30 minutes, five times a week.

That breaks down to 100 steps a minute, which may sound like quite the pace. While it's no leisurely stroll, it won't win you a medal in the 100-metre sprint. Think walking quickly to get to a meeting.

Nobody's going to go around counting steps for half an hour. However, lead researcher Simon J. Marshall says you can do it with a pedometer and a watch. Pedometers are pretty accurate when it comes to counting steps, but they won't measure the intensity of your workout. Count your steps for a couple of minutes, and you'll get a pretty good idea of your pace.

After half an hour of this – if you're not totally out of shape - you'll feel like you've had a workout. Not exhausted, but moderately tired.

Marshall notes that half an hour at a time may sound daunting to a lot of people. His advice: break it up. Your body benefits from workouts as short as 10 minutes. So instead of looking at this mountain of 3,000 steps, you'd get the same benefit by doing 1,000 steps in 10 minutes, three times a day – on level terrain.

It's a small change that – over time - can yield more than moderate results.