Why We Eat When We Know We Shouldn't

I'm full, so why do I keep eating?

There are many things that trigger us to eat. Maybe you were taught to clean your plate, or maybe everyone in your family always ate second helpings. Sights, sounds, smells, situations, locations, emotions- all may trigger appetite, which is the desire to eat.(1,2)  It is important to understand what drives appetite so as to minimize the negative impact of an appetite gone awry. Before we get too far into this topic, let's get a little terminology out of the way.

1.    Appetite- the desire to eat (not a physiological need)
2.    Hunger- the physiological need for nourishment
3.    Satiety- a feeling of fullness and lack of desire to eat


Weight gain and satiety

When one is in a weight gain cycle, fullness is a familiar feeling. While maintaining weight, we may often feel sated, although it probably occurs less frequently. When losing weight, satiety is very rare and hunger pangs become the norm.  But as everyone knows, hunger often has nothing to do with eating.

Why do we consistently eat or drink beyond our needs? There are as many reasons as there are overweight people in the US. The trouble is that the potential solution varies from person to person because of the complexities of human psychology and physiology. With so many factors driving us to eat, most people are faced with the seemingly inevitable slow-but-steady weight gain that plagues society(4).


Saving calories for a rainy day

Appetite and satiety work together to maintain energy stores and body weight.(5,6)  Due to the nature of human survival, the relationship between appetite and satiety encourages food intake and energy storage.(7)  This becomes a problem when you try to reverse unwanted weight gain and true satiety becomes virtually non-existent. This is because, as discussed above, the feeling of fullness only happens when the trend is weight gain or at certain times during maintenance. Your body worked hard to gather and store those extra calories, and based upon inborn survival mechanisms, the body will try to hold onto them for that “rainy day” when a consistent, reliable food supply disappears. In today's world, though, this day never comes.

Now you know why it is virtually impossible to feel regularly full when dieting. Dieting and purposeful food restriction both go against your body’s instincts, regardless of whether you’re ten pounds or 200 pounds overweight.

While dieting, there are moments of agonizing, uncontrollable hunger. The further you stray from your starting weight, the more severe the struggle. Deeper into your diet, you begin to become increasingly aware of food . . . it's everywhere! You might find yourself obsessing over your next meal and even unconsciously find yourself looking at pictures or signs of foods. Cravings become common and food you never even really liked before looks appealing. As hunger continues to mount, you may start to feel crabby and even go so far as to be annoyed with people for having the audacity to eat anywhere near you. Little by little, the body and mind work on you and without your awareness, you may begin to increase your portions a bit. You formulate excuses as to why it is okay to "cheat" for a meal or two (or three). Finally, you start to plan what you will eat when you eventually lose the weight and complete your "diet". It is amazing all of the subtle and not so subtle tricks the body employs to get you to increase your food intake. Dieting is not natural and it is a small percentage of people who succeed at weight loss and maintenance and appear to have “beat the system”. But don’t worry, there is hope.


Know your enemy

Now we realize what drives us to eat (hunger), and we also know that in today's “land of plenty”, finding and storing food is NOT the problem. The trick is identifying when you’ve had enough and suppressing the urge to eat when you know you don’t need to.

If you’re overweight, or like many people have that roll of fat that never goes away, there is no physical or physiological reason to gain weight (you have plenty of energy stores). Nor should you have an internal “lingering” hunger cue following normal meals. So what continues to drive us to eat? External cues, learned behavior and the environment in which we exist. Memories, experiences, emotions, habits, sensory stimulation and situations can all trigger our appetite and motivate us to eat more.(8,9,10,11,12)  Of course the simple solution is to move to a deserted island (ever notice how everyone on Survivor loses weight?), but since that’s not likely to happen, we are left with altering our environment.

Recall that appetite is influenced most often by our environment: in social or other situations, we drink when not actually thirsty, and eat when not hungry simply because the food is there or it gives us something to do.


Sound familiar?

• You cruise into your favorite coffee shop for a small coffee, but you order a 200-400 calorie beverage instead (e.g. latte or mocha)
• You go out with friends for a few drinks (which of course contain calories), not because you’re thirsty, but to “hang out”
  • A few drinks often become quite a few drinks
• A "few drinks" is infinitely more enjoyable with a few munchies (generally high in fat and calories)
  • As more drinks are consumed, the ability to make wise food choices diminishes(13)
• You clean your plate because that’s what you always do, not because you know it’s exactly the amount of food you need
• Dinner and a movie is almost invariably dinner and a movie and snacks (even though you ate PLENTY at dinner)

What the folks in lab coats have to say

In an important recent study related to satiety, researchers discovered that people “count calories with their eyes and not their stomachs”. Researchers conducted a test using a “bottomless soup bowl” (self-refilling bowl) with one group and a normal bowl of the same size with another group. Participants using the bottomless bowls consumed 73% more soup than the other group.(14)  Without the visual cue of the diminishing soup, people were misled into thinking they had not eaten as much as they had, so they kept eating. Here are a few more findings on how the environment affects eating:

• People who eat with others consume 44% more food than when eating alone
• Women eat 13% more in the company of men than when eating with other women
• Snack size, variety of food options, visibility and proximity to food influence how much is eaten
  • At a movie, people eating popcorn from a large bucket ate 33% more by the end of the film than those eating from a medium bucket (even though both groups had previously eaten dinner and the popcorn was 14 days old)
  • When provided with a variety of snack foods (e.g. yogurt, jelly beans, M&M’s) people ate up to 70% more calories
  • People ate Hershey’s kisses at a 46% faster rate when in a clear jar versus an opaque one
  • People ate 5.6 more candies/day when the candy jar was on their desk versus 2-yards away

So what do I do?

Other than our waistlines, we are no different from our ancestors when it comes to satiety. Our early predecessors also ate everything around them. The difference was they didn't have the quantity and variety of foods that we encounter every day. They didn't have the luxury of drive thrus, buffets and snack machines. Our ancestors had to grow it, gather it, catch it (or run from it), and prepare it. The work required to acquire food and stay alive kept people skinny. Taking a page from the past can help guide us to control our weight and appetite: 1) stay busy; 2) a calorie burned offsets a calorie eaten; 3) make food scarce (do not stock your home or surround yourself with a variety of yummy, calorie rich food-if it’s not there, you can’t eat it).

If we had to acquire food as our ancestors did, we would certainly solve society’s weight problem. The energy we would spend to get it would offset the calories we ate once we found it.(15)  What is interesting is that the very traits that led to our survival are now killing us: we are hardwired to seek out food and eat all we can once we find it.


Tricks of the trade

To gain some insight into hunger and how to deal with it, we can look at a group of athletes who truly understand what it is to lose fat (almost all of it) and deal with insane hunger while still trying to function as members of a civilized society. A competitive bodybuilder endures more hunger and food restriction (read misery) than anyone on the planet (who has the luxury of choice).

As such, they have come up with some imaginative and effective methods to take the mind off of food. Here are a few examples:

• Brush your teeth immediately following a meal: it sends a subliminal message that the meal is over
• Stick sugarless gum in your mouth every time you get an urge to eat or keep eating when you shouldn’t
• Drink a diet soda, coffee or tea when an eating urge occurs, or to end each meal
• Eat slowly and wait 40 minutes after a meal before you decide to give in to dessert or more food; it takes roughly that long for the satiety message to get from your stomach to your brain
• Stay busy: plan an activity almost immediately post-meal or between meals where eating would be difficult or impossible to do
  • This increases your calories burned rather than your calories consumed, refocuses your attention, and stalls for time until the satiety signal hits
• Consume foods high in volume and low in calories e.g. BIG salads
• Use non-caloric sweeteners to satisfy a growing sweet tooth
• Go to bed early, or save a meal for right before bedtime – you can’t eat when you’re asleep, but you’re more likely to eat more if you go to bed a long time after dinner
  • Humans are always less hungry in the morning than they are at night
• Take your time eating – take small bites and use small utensils
• Snack on pickles or air popped popcorn when you just have to eat
• When all else fails and you are tempted to make a poor food decision, pinch that spot of fat you’re trying to lose and think again
• When your sweet tooth becomes unbearable (the leaner you get the louder it screams) be sure to save the calories you need to satisfy it – but get the most bang for the fewest calories. If you can, try a lower fat/calorie/sugar option, it may just work
  • dotFIT breakfast bars and protein sticks can be a guiltless dessert that will actually add the proper protein, carbs and fats that you need. Try microwaving them for 20 seconds . . . wow.

Don't Let Your Environment Go To Your Waist (tips for fat-proofing your world)

• Before completing your meal, have the breadbasket removed or have a portion of your entrée boxed “to go.” The atmosphere of a long and relaxing dinner can then be enjoyed without the temptation to overeat
• Although soft music and candlelight can improve one’s enjoyment of a meal, they have calorie intake consequences. Instead of automatically eating a dessert, enjoy a cup of coffee in the pleasant atmosphere
• Make tempting foods harder to get to, putting them in inconvenient locations (such as in a basement or in a top cupboard or buried under the driveway)
• At mealtime, portion out your plate in the kitchen rather than having extra food on the table within arm’s reach
• Decide how much to eat prior to the meal instead of during it. Order smaller quantities (e.g. half-size portions) to avoid excess calories
• Model the behavior of a person eating the least or the slowest
• Discourage “grazing” by focusing only on a meal and only when sitting down, preferably at a distraction-free table
• Don't eat while doing other activities like watching TV or reading. If for some reason you ignore this advice, then pre-serve the portions and allow no “refills”
• Eliminate the cookie jar. Replace it with a fruit bowl
• Position healthy, lower calorie foods in the front of the refrigerator and the less healthy foods in the back
• At buffets and receptions avoid having more than two different foods on the plate at the same time
• Repackage foods into smaller containers to get used to smaller portions
• Plate smaller dinner portions in advance
• Never eat from a package. Always transfer food to a plate or bowl in order to make portion estimation easier
• Out of sight is out of mind. Don't buy or store poor food choices. The work involved with getting them gives you time to reconsider making a bad choice
• Stockpile healthy, low-energy-density foods (few calories per ounce or item) to stimulate their consumption and to leave less room for their high-density counterparts
• Replace short wide glasses with tall narrow ones; it looks like you drank more
• Reduce serving sizes and consumption by using smaller bowls and plates
• Use smaller spoons when serving; it's more work and it makes you feel like you've served a lot

References 

1.   Birch LL, Fischer JO. Development of eating behaviors among children and adolescents. Pediatrics. 1998 Mar; 101 (3 Pt2): 539-49.
2.   Herman CP, Polivy J. External cues in the control of food intake in humans: the sensory-normative distinction.
3.   Das SK, et al. Long-term effects of 2 energy restricted diets differing in glycemic load on dietary adherence, body composition and metabolism in CALERIE: a 1-y randomized controlled trial. Am J Clin Nutr. 2007 Apr;85(4):1023-30.
4.   Jeffery JW, French SA. Preventing Weight Gain in Adults:The Pound of Prevention Study. American Journal of Public Health; May 1999, Vol. 89, No. 5: 747-51.
5.   Berthoud HR. Mind versus metabolism in the control of food intake and energy balance. Physiol Behav. 2004 Jul; 81(5): 781-93.
6.   Hunt SM, Groff JL. Advanced Nutrition and Human Metabolism. St. Paul, MN: West Publishing Company; 1990. 517pgs, pp411-414.
7.   Malik S, McGlone F, Bedrossian D, Dagher A. Ghrelin modulates brain activity in areas that control appetite behavior. Cell Metab. 2008 May; 7(5): 400-409.
8.   Hetherington MM. Cues to overeat: psychological factors influencing overconsumption. Proc Nutr Soc. 2007 Feb; 66(1): 113-23.
9.   Herman Cp, Polivy J. External Cues in the control of food intake in humans: the sensory-normative distinction. Physiol Behav. 2008 Aug ; 94(5): 722-8.
10. Polivy J, Herman CP, Coelho JS. Caloric restriction in the presence of attractive food cues: external cues, eating and weight. Physiol Behav. 2008 Aug; 94(5): 729-33.
11.   Jansen A, Theunissen N, Slechten K, Nederkoorn C, Boon B, Mulken S, Roefs A. Overweight children overeat after exposure to food cues. Eat Behav. 2003 Aug. 4(2): 197-209.
12.   Jansen A, Vanreyten A, van Balveren T, Roefs A, Nederkoorn C, Havermans R. Negative affect and cue-induced overeating in non-eating disordered obesity. Appetite. 208 Nov; 51(3): 556-62.
13.   Hofmann W, Friese M. Impulses got the better of me: alcohol moderates the influence of implicit attitudes toward food cues on eating behavior. J Abnorm Psychol. 2008 May; 117(2): 420-7.
14.   Waink B, Painter JE, North J. Bottomless bowls: why visual cues of portion size may influence intake. Obes res. 2005 Jan; 13(1): 93-100.
15.   M Hayes M, Chustek S, Heshka Z ,Wang A, Pietrobelli and SB Heymsfield, SB Low physical activity levels of modern Homo sapiens among free-ranging mammals; International Journal of Obesity (2005) 29, 151–156