It's a battle royale, with cheese. In one corner of your mind, there's the satisfaction of that trim, hard body you've built.

In the other, there's the hamburger - juicy, tasty, covered with a blanket of melted Cheddar. Or maybe your struggle is against crispy fish and chips. Or pizza. Hard to believe there ever was a time when mankind could be seduced by an apple, isn't it?

To avoid temptation, you could wire your refrigerator to deliver a shock every time you open the door. Or you could continue eating pizza, nachos, burgers - all of your favourite comfort foods - without guilt. It can be done. With a few easy tweaks, just about any food can be transformed into good stuff that satisfies your nutritional needs and your tastebuds.

Make your foods this way and you'll have our blessing to pig out.

BURGER

What's so bad? Ground beef is shot through with fat and that white-bread bun offers little but rapidly digested starches.

Make it better: start with extra-lean ground beef - if you don't overcook it, it'll taste great. Chop up some onions and thawed frozen spinach and mix them into the beef. The vegetables add vitamins and replace some of the moisture lost when you switched to leaner ground beef. Better yet, build those burgers with kangaroo mince, at less than two per cent saturated fat. Researchers at Purdue University in the US found that wild game have higher levels of good-for-the-brain and good-for-the-heart omega-3 fatty acids. Top it all off with a wholemeal bun for some fibre.

You gain: allicin, 47 micrograms (mcg) beta-carotene, 5g fibre.

GRILLED-CHEESE SANDWICH

What's so bad? The 18g saturated fat you take in from the butter and slabs of oily cheese. And the white bread is pointless.

Make it better: use wholemeal bread with part-skim mozzarella in between. Crisp it in a pan moistened with a little olive oil.

Losing the finger-licking buttery bliss is worth it.

A recent study in the Journal of the American Medical Association found that an olive oil-rich diet can drop your chances of dying of cancer or heart disease by 23 per cent. To protect your prostate, add a couple of lycopene-packed tomato slices. Likely to work late? Throw in a slice or two of lean ham. That will jack up the protein count, keeping your appetite in check.

You gain: 11g protein, 5g fibre, 1000mcg lycopene.

PIZZA

What's so bad? Oil-pooling peperoni, to start. Then a huge kilojoule count that comes mainly from refined carbs and saturated fat.

Make it better: opt for a thin crust (fewer refined-flour carbs), use half the cheese and replace the peperoni or sausage with chicken breast, a lean protein that has less than 1g fat per 25g. (A little barbecue sauce is okay. Great, in fact.) The chicken gives you more muscle-building protein and a ratio of protein to fat that better satisfies the appetite. Add some sliced onions and capsicum to rack up a little fibre and some immune-boosting allicin.

You gain: allicin, fibre, twice the protein.

FISH AND CHIPS

What's so bad? There's fat everywhere - the battered and fried fish, the greasy potatoes and the creamy coleslaw.

Make it better: you love the crunchy crispiness, right? Try pan-seared salmon - it'll crisp up beautifully - for a healthy dose of cholesterol-lowering omega-3 fats and a potential brain boost.

A study on mice by the University of California in Los Angeles suggests that DHA, one of the fats found in high levels in fish like salmon, helps repair memory damage caused by Alzheimer's disease.

Roasted potato wedges sprayed with a little olive oil are infinitely better than fat-soaked fried chips.

Grab a bag of finely chopped coleslaw mix at the supermarket and use either low-fat mayonnaise or, better yet, a tangy vinegar-and-oil dressing.

You gain: 4g omega-3 fats.

NACHOS

What's so bad? Just 13 ordinary corn chips contains 500kJ and 6g fat and you haven't even ladled on the cheese product, the greasy spiced hamburger mixture or the sour cream. Do that and you're hoisting 26g of saturated fat into your mouth.

Add thirst-inducing, pickled-jalapeno-chilli slices and you're getting a day's worth of sodium in this 4719kJ pile.

Make it better: start with baked corn chips (less fat), add cooked pinto beans for fibre and use reduced-fat, mature Cheddar and lean ground steak. Top with cancer-fighting, diced tomatoes (for lycopene) and diced, fresh jalapeno peppers - it has no added salt, but still delivers plenty of kick. The whole concoction is leaner, tastier and heaps better for you. Go ahead, have some more.