Melanie Leyshon is the editor of Healthy Food Guide magazine. She's a flexitarian and couldn’t get through the week without yogurt and yoga.

We asked Mark what keeps him on the straight and narrow after the holidays

Do you succumb to excesses over Christmas?
Like everyone, I worried less than usual about my arteries and liver and consumed far more than I needed to. My particular downfalls are good wine, beer with my mates in the pub (who I don’t see as often as I’d like) and my wife Ros’s mince pies (the world’s best).

Have you ever dieted to shift the weight quickly?
No. I start the week a couple of pounds above 14st, and end it a pound below. It’s been that way for 20 years. Left to my own devices, I’m a picker, but work fixes that (as long as patients don’t leave too many chocolates for the reception staff).

How do you get back on track in the new year?
I rarely need to. A couple of weeks at the grindstone will normally shed any excess flab. If I had to lose more, I’d opt for a low-carb diet – I eat far too much bread and the weight falls off me when I cut down.

Do you ever struggle with good intentions?
I am no saint. My main weakness is that I start every day with buttered toast covered in ginger preserve – and have done for years. I only order wholemeal/seeded loaves when I’m feeling guilty, which isn’t that often. And I eat far too much cheese – tasty cheddar (the stronger the better) being my favourite.

Are you more concerned with weight issues than when you were 20 or 30?
I’m a stone heavier but at 6ft 3in I’m happy where I am. I can still get into the morning suit I wore when I was married in 1987 – albeit a snugger fit these days.

Do you take health checks?
I know my cholesterol level (too high, thanks to my genes – and possibly my love of cheese) and blood pressure (good). It makes sense to be aware of your body, report symptoms early and take care of yourself. But don’t go looking for trouble – don’t have any ‘screening’ test unless it’s offered on the NHS (where it’s been validated and proven to do more good than harm). I’ve seen too many patients being unnecessarily scared or harmed by private tests and inappropriate investigations. My first NHS screening test will no doubt be a camera into my bottom to look for bowel cancer or polyps that can turn cancerous – something that will probably soon be offered to every middle-aged man and woman in the UK (it is currently being piloted). I shall take up that invitation.

What’s the one bit of health advice that makes all the difference?
Exercise regularly. And the older you get, the more important it is. I train three times a week in a gym and go for a run/walk with the dog at weekends. It’s good for your heart and brain, reduces the risk of cancer, helps you stray trim, gives you more energy and means you can pick things up off the floor without groaning.

Three things I love

MUDDY RUNS An ideal Sunday morning is a run along muddy woodland paths in the rain with my dog. We both get filthy. Then it’s home for a shower and a read of the papers by the fire.

DRIVING If I need time to myself, I often go for a drive in my 30-year-old Mercedes SL. It’s hardly fast – you sail it rather than drive it – but it takes me back to a simpler time with no mobiles, email or internet.

BLACK PEPPER I have it with almost everything.

Related article: How I stay healthy: Davina McCall