We're continuously eating bigger portions than we should.
This makes sense: We're geared to eat as much as possible and to hang on to it as long as we can, says Pawel Olszewski, senior lecturer at the Department of Biological Sciences at the University of Waikato.
"It's only in the last few decades that food has been readily available at a relatively low price," he says.
On top of that, we are very poor calorie counters. Studies prove that if we're given a portion of food, we will finish it, no matter how big.
A fascinating study of the art of the last millennium proves just how our perception of a normal serving size has changed.
Brian and Craig Wansink, the brothers behind the study, analysed 52 paintings of the Last Supper over the last 1000 years and found that the food and platters placed before Jesus Christ and his disciples have grown over the years. The results showed that the relative sizes of the various dishes, compared to the size of the subjects' heads, have increased in a linear fashion over this time.
And not just by a little bit. The main dish has increased by 69 per cent, the bread by 23 per cent, and the size of the plates by 66 per cent.
"To me, this is phenomenal," says Olszewski. "How artists would treat the last supper - even how they would treat Jesus well, by giving him more food and expecting him to eat more, is telling. It shows that how much we eat is cultural and subconscious."
It's a case of art imitating life.
The size of everything from cheeseburgers to muffins has grown enormously since the 1960s, studies show.
And this portion creep, as experts call it, is taking its toll. "In every developed country in the world, more people are becoming obese," Olszewski says.
Bigger plates, bigger portions
But it's not just our portion sizes that have increased. In the 1960s, the average dinner plate was 25.4cm. Now, it's 30.5cm.
And the mind is a tricky thing. We'll pile more food on to our plate if it's bigger, less if it's smaller, studies show.
The Small Plate Movement encourages people to eat off a 9- to 10-inch (22.86cm to 25.4cm) plate for their largest meal of the day for at least a month. And people are seeing weight loss results because of it, the organisers claim (sign up at smallplatemovement.org).
While a smaller plate might help you eat less, people still get a lot of their calories from snacking, says Olszewski.
"A healthy snack is one that is eaten rarely."
The quality of the snack is also important. Don't eat empty calories - foods that are low in vitamins, minerals and nutrients and high in calories per gram.
Use your hands
So how much should we be eating at mealtimes? When measuring out portions, it's a good idea to use your own hand as a guide - this means you'll always be eating for your body size, says Hamilton dietitian Katharine Olson.
Protein: the size of your palm (excluding fingers) and the thickness of your hand. This equates to about 100g of meat, 1 chicken leg or two drumsticks (110g) or cup of mince (195g). If you're making a curry or casserole, use about 120g of uncooked meat per person - 150g if it's lean meat like a chicken breast.
As for carbohydrates, use the size of your clenched fist, so one medium potato or kumara (135g) or cup of pasta (195g).
As for non-starchy vegetables, you can eat two cupped hands' worth.
Portion sizes often get out of control because we don't eat regularly enough, says Olson, so always have breakfast, lunch and dinner.
"If we skip a meal, we're more likely to pile up the food for our next meal."
Keep the plate model in mind. Your plate should roughly consist of a quarter protein, quarter carbs and half vegetables. "Serve veges first. Often when we serve carbs and protein first, we get carried away."
This is also a great way to stay in charge of what you eat at a pot luck meal, barbecue or event with a buffet dinner.
Savour your meal
Think about the taste and sensation of the food and chew slowly. Too often we wolf down our food without giving it a second thought.
"And I always tell my clients, if you've eaten your meal and you still feel hungry, wait half an hour."
Our bodies don't always tell use that we're satisfied straight away. If you're still hungry, have a healthy snack like a reduced fat yoghurt or fruit.
Make a plan
ake control of snack portion sizes by dividing your healthy snacks into smaller bags. This way, you can grab 30g of nuts before you leave home for work, instead of lugging the bargain-size bag with you and being tempted to eat more.
Think similarly with dinners: cook beforehand and freeze individual portions, ready for when you get home after a long day and need something quick. It will make it easier for you to say no to fast food options, too.
Remember to check the serving size. That bar of chocolate you gobble in one go might say 500kJ per serving, but if you look carefully, it's listed as two servings. That means 1000kJ for the whole thing.
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