Diet Myths & Eating Psychology
Your Guide to Eating and Living Well

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OVERVIEW

There's a litany of dieting advice that claim healthy results, but do not deliver on their promises. Promoters of certain fad diets and even well-intentioned nutritionists either do not keep abreast of food science research or ignore certain biological facts. And recent research demonstrates psychological influences play a more significant role with eating habits than most people realize.

 
COMMON DIET MYTHS

MYTH: DRINK 8 OUNCES GLASSES OF WATER 8 TIMES A DAY. FACT: This practice just doesn't hold water. There is no scientific research that has ever validated any of the claims that drinking any specific amount of water or fluids affect weight-loss, makes you less hungry, flushes the toxins from your body, improves your skin tone, or mitigates headache pain. It's hard to pindown how this myth originated and then became so entrenched in dieting counsel.

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.

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.

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

MYTH: Cravings are your body's way of telling you it needs something. FACT: Cravings are driven by emotions and we often crave foods we enjoy and associate with pleasurable times. Of course, hormonal changes can be responsible for cravings - like ice cream and pickles.

MYTH: Granola bars are a healthy snack. FACT: Most granola bars are simply expensive candy bars - loaded with carbs, calories and sugar.

MYTH: Egg-White Omelettes are superior to those made with regular eggs. FACT: No - Half the fat in the yolk isn't saturated and contains several brain and vision healthy nutrients.

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

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.

MYTH: Eating more slowly helps us to eat less. FACT: Research shows that this 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.

 
THE PSYCHOLOGY OF EATING

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.

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