1) MYTH: Calories eaten after 8PM turn to fat. FACT: There is no intrinsic connection between calories and the clock. No matter what, whatever calories you do not burn during the day will be stored as fat.

2) MYTH: To jump-start your diet, you should fast. FACT: Though fasting may temporarily help you lose weight, it's predominantly water weight.

3) MYTH: Low-carb (high protein) diets are the most effective route to weight loss. FACT: Studies show that obese people can lose more weight on a low-carb diet than on a conventional low-fat diet, but they usually regain the weight after six months. It's still about calorie intake and what you burn off.

4) MYTH: Drinking lots of water will help you lose weight. FACT: First, staying hydrated is importnat, but the amount of water we've been told to drink a day is too much. Water won't flush away calories - and even if you fill up your stomach, your body still signals your brain to eat some food with nutrients.

5) MYTH: Eating liquid meals shrinks your stomach. FACT: The stomach is a muscular organ that stretches to accomodate what you eat. There's nothing you can do to permanently shrink it.

6) MYTH: Exercising on an empty stomach burns more fat. FACT: You should eat 3-4 hours before a workout.

7) MYTH: Eating grapefruit burns fat. FACT: This is the most persistent dieting myth. There is no food that has "fat-burning enzymes" that magically melt fat from your body. However, they're rich in lycopene - an antioxidant that protects against heart disease and breast cancer.

8) MYTH: Eating more slowly helps us to eat less. FACT: Research shows that thi indeed may be helpful to men, but doen't work for women. It could be that men eat much faster and women eat at a more leisurely pace to begin with, so there wasn't much additional affect.

INTERESTING FACT: The effect of portion size on how much people eat is something of a mystery – why don’t they simply leave what they don’t want, or alternatively, where possible, why not help themselves to more? Andrew Geier and colleagues at the University of Pennsylvania think it has to do with ‘Unit bias’ – “…the sense that a single entity (within a reasonable range of sizes) is the appropriate amount to engage, consume or consider”.

To test this, the researchers left a bowl of M&M sweets in the hallway of an apartment building with a sign that read “Eat Your Fill: please use the spoon to serve yourself”. Some days they left a tablespoon-sized scoop, other days they left a quartercup scoop that was four times as big. Passers-by could obviously help themselves to as little or as much as they wanted regardless of which spoon was provided, but on average, 1.67 times more M&M’s were taken on the days the big scoop was left compared with the tablespoon-sized scoop.

In another experiment, the researchers found that, measured by weight, significantly more pretzels were taken by passers-by when a complimentary bowl of 60 whole pretzels was left in an apartment building, compared with when a bowl of 120 half-pretzels was left. And it was a similar story when either a bowl of 80 small Tootsie rolls (an American snack bar) or a bowl of 20 large Tootsie rolls was left in an office building.

In other words, throughout the study, people took more food when the unit on offer was larger. “Consumption norms promote both the tendency to complete eating a unit and the idea that a single unit is the proper portion”, the researchers said. However, they also acknowledged that other factors must have been at play because the amount of food taken did not vary in direct proportion with the increase in unit size on offer.

The researchers concluded that this ‘unit bias’ applies in other walks of life too – they cited the example of films: “double features are rare, but very long movies are not”, and amusement-park rides: “one ride on a particular attraction is usually enough, whether it takes one or five minutes”. _________________________________ Geier, A.B., Rozin, P. & Doros, G. (2006). Unit bias. A new heuristic that helps explain the effect of portion size on food intake. Psychological Science, 17, 521-525.