Fit in your 30s

The melt fat decade
The metabolic rate that allowed you to burn through tikka masalas in your 20s is gradually slowing by one per cent every four years. And even if the figure on your scales isn't rising, it doesn't mean you aren't becoming any fatter. In a study published by the American Journal of Clinical Nutrition, scientists found that men who managed to maintain their weight for 40 years still gained three pounds of fat each decade, pounds they directly exchanged for muscle.

The primary reason is that past the age of 30 your testosterone levels decrease by up to one per cent a year. This means it becomes harder for you to build or simply maintain metabolism-boosting muscle. But sagging testosterone levels aren't your only health hazard: from now on your systolic (in other words, peak) blood pressure rises by four points per decade and joint degeneration begins to occur.

To prevent the onset of midlife kicking you in the teeth, here's how to wind back the hands of your biological clock.

The problem
Corroding joints
Arthritis doesn't usually start reeking havoc until you hit your 50s, but the damage that causes it is happening now. Neglect to take the appropriate care now and you can think of it as missing down-payments on your health mortgage. The key is to act before your joints are repossessed.

The fix
Guess what? The answer's fish again. Sorry, but it's inescapable: eat a hearty portion of cold-water fish three times a week, specifically oil-rich varieties such as salmon, mackerel, trout or halibut. With each serving packing more than 1,000 mg of fish oil, regular consumption has been shown by a recent study to halt cartilage-eating enzymes in 86 per cent of people facing joint-replacement surgery. According to lead researcher Dr Bruce Caterson, fish oil slows down cartilage degeneration and reduces inflammation.

The problem
Rising blood pressure
Some men are always close to their boiling points, and new research from Holland may explain why. Scientists discovered that besides the obvious factors – obesity, lack of physical activity, high salt consumption – diets containing too little potassium were the primary cause of hypertension. Their analysis concluded that 3,500mg daily constitutes a low potassium intake, a worrying conclusion when the average intake for a man in his 30s is just 3,100mg.

The fix
Add 1⁄2 cup of kidney beans, a banana or a handful of raisins to your daily diet. Each will increase your potassium intake by about 400 mg a day, boosting you above that 3,500 mg threshold.

The problem
Waning sex drive
Yes, it happens, no matter how much your better half complains of your one-track mind. For all your 20s exuberance and ribald pub banter, one of the less frequently uttered grievances of a man in his 30s is a slow withering of the inclination to display his athleticism come bedtime. And no one wants that.

The fix
Munch on two handfuls of walnuts, peanuts or almonds every day. Research shows that men with diets high in mono-unsaturates - the kind found here – have higher testosterone levels than those who shun the healthy fat. Nuts are also the best food source of arginine, an amino acid that improves bloodflow throughout your body, including the areas south of your belt.

The problem
Your metabolism is slowing
It's a fact of life that your body is slowing down, but that doesn't mean you have to take it lying down. By snacking on foods that are low in sugar but rich in protein you'll keep your metabolic furnace stoked and be less likely to binge between meals.

The fix
Nibble on a slice of hard cheese (Cheddar, Swiss, parmesan) three times a day and you'll be swallowing in the region of 20g of protein. The fact cheese doesn't contain any sugar means that your blood-sugar levels stay low and stable and your body stays in fat-burning gear. But if a slice of mousetrap isn't your thing, opt for a cup of low-fat plain yoghurt or a stick of beef jerky; better still, kill two birds with one stone and grab a handful of almonds (see Waning sex drive above).

The problem
You can't lift the weights you used to
As a kid you probably have looked on your dad as the embodiment of manly strength, but the chances are his apparent mightiness was already on a downward spiral. As testosterone levels inevitably drop with the onset of your thirties, the cruel rules kick in as it takes longer for your muscles to return to full strength after each workout.

The fix
Eat broccoli and bell peppers at every opportunity. Together they're packed with vitamins C and E, two nutrients which fight the free radicals that slow the repair of exercise-induced muscle damage. Try this 15-minute meal from a man who knows a thing or two about workout recovery: MH cover model Gregg Avedon. Infused with crucial vitamins, high-quality protein and slow-digesting carbohydrates, it's the perfect meal to whip up after a strenuous weights session.

1. In a deep saucepan, sauté 1 tablespoon of chopped onion, 1⁄4 of a red bell pepper (cut into long, thin strips) and a pinch of black pepper on medium heat for 2 minutes.
2. Next, add 250g of turkey breast strips and 1 teaspoon of dried sage.
3. Brown the turkey for 2 minutes, then add 200ml of chicken broth and a good fistful of broccoli florets.
4. Bring to a boil for 1 minute, then stir in some plain, uncooked couscous.
5. Cover the pan, remove from the heat, then let it sit for 5 to 10 minutes. Serve when the couscous has absorbed all the liquid.