The old saying goes, "you are what you eat" but how much do you really know about food, and the effect it has on your body?

It can be hard to sift through the myriad conflicting advice about nutrition and healthy eating, and research shows that Australians are fatter than ever before.

According to ABS research, many Australian men and women aren't getting all the calcium and iron our bodies require. But we still see ourselves as healthy, with over half of all Australians aged 15 or over saying they are in good or excellent health.

We are also wasting massive amounts of food, some $8 billion worth each year.

ABC Fact Check takes a look at food and nutrition.

1.

Seven per cent of Australians (around 1.6 million people aged over 2) avoid certain kinds of food for cultural, religious or ethical reasons. According to the ABS, 3.9 per cent avoid pork, 2.1 per cent avoid all meat, and 1.6 per cent avoid beef.

Pigs on a pig farm in Colombia in April 2009. ( AFP: Raul Arboleda )

2.

The production of single kilogram of meat can require between five thousand and ten thousand litres of water. A kilogram of wheat requires about 1000 litres of water to produce. The agriculture industry is the biggest consumer of water in Australia, accounting for 52 per cent of total water consumption.

3.

Have you ever seen a strange glow coming off some uncooked pork, chicken or other meat? Don't worry, it's almost certainly not radiation, but some meat actually glows in the dark. Bacteria on the surface cause a blue-green bio-luminescent glow. The bacteria called pseudomonas are destroyed by proper cooking and don't cause food poisoning, but the strange glow might put you off your dinner. But microbiologists say they wouldn't recommend you eat meat that is glowing as it indicates it hasn't been properly refrigerated and close to spoiling, and could pose a health risk.

The RSPCA opposes eating cats and dogs

4.

In most Australian states and territories it is not an offence to eat cats or dogs. South Australia is the only state to prohibit it. However according to the RSPCA, the sale of meat from cats and dogs is effectively prohibited by various laws relating to animal cruelty and food safety. The RSPCA opposes eating cats and dogs because of their "place in Australian society as companion animals and close working partners of humans".

5.

Seventeen per cent of Australians (around 3.7 million people aged over two) say they avoid certain foods because they have an allergy. The most common allergy or intolerance is to dairy products (4.5 per cent), and then gluten (2.5 per cent), shellfish (2 per cent), and peanuts (1.4 per cent). Another 8.5 per cent of people report allergies or intolerance of "other" foods including tomatoes, oranges, bananas, capsicum and general food types, such as "spicy food", acidic food or food with preservatives.

6.

Some people develop a condition from eating pine nuts called "pine mouth" or "pine nut syndrome". Sufferers can experience a metallic taste in their mouth after eating pine nuts or products containing pine nuts like pesto. The aftertaste only develops a few days after eating the pine nuts, and can last for up to two weeks. The cause of "pine mouth" hasn't been determined, there are no adverse health effects, just a funny taste.

Young children eat less vegetables than older children, the ABS says. ( ABC News: Ian Cutmore )

7.

Experts say we should eat five serves of vegetables and two serves of fruit per day for good nutrition and health. Just 8.3 per cent of Australians aged over 18 say they eat the recommended quantity of vegetables, and 48.3 per cent consume the recommended amount of fruit. Women and older people are more likely to eat adequate fruit and vegetables.

8.

Around 63 per cent of Australian adults are overweight or obese, and more men are fat than women: 70.3 per cent of men and 56.2 per cent of women are overweight or obese. But among children, more girls are overweight or obese than boys: 27.1 per cent to 23.6 per cent.

9.

Between 2007-08 and 2011-12 the average waist measurement for Australian men went up (or out) 1.7 cm to 97.9 cm, while women's waistlines bulged 1.9 cm to an average of 87.7 cm.

10.

The United Nations estimates there are 805 million people in the world who are experiencing chronic hunger. 5 million children under the age of five die of malnutrition-related causes every year.

A Turkana woman walks carries food rations as she leaves a relief distribution centre at Lokitaung in Kenya. Drought in the Horn of Africa and the famine in Somalia has left more than 2 million children at risk of starvation. ( AFP )

11.

"Use by" labels apply to food which can become unsafe to eat before it noticeably spoils, or can decline in nutrient levels if it's intended to be the sole form of food in someone's diet. "Best before" dates apply to food which may spoil and lose taste or satisfaction, but doesn't affect health and safety. Food with a shelf life of over two years doesn't require either label.