"...And now they’ve entered the starting gate. In the #1 post position...16 healthy rats that have been in training on a restricted-calorie diet. They are Hungry! And running against them...16 healthy rats that are well fed and have just finished a meal. They are Not Hungry! At the finish line.....a European breakfast cereal: Choc’n Crisp!"
Yet another delight for chocoholics! Choc’n Crisp is a chocolate flavoured crispy toasted rice extrudate full of vitamins. It tastes exceedingly chocolatey and ensures strength and vitality all day long.
Welcome to the continuing diary series, "Let's Read a WHEE [Weight, Health, Eating and Exercise] Book Together!" Today, we're continuing with David Kessler's The End of Overeating, Ch. 6, "Sugar, Fat and Salt Are Reinforcing." If you want to follow along but you can't get your hands on a copy of Kessler's book just yet, you can read the first six chapters on Google Books, if you have the right browser.
"And they’re off!" For the exciting finish of today’s race, grab your binoculars and follow the rodents over the fold!
"What a suspenseful race, ladies and gentlemen! The Hungry Rats prevailed by a nose, but those Not Hungry rats made it a close run all right! And look at that! The Not Hungry Rats are digging into that Choc’n Crisp with just about as much gusto as the Hungry rats! That crunchy, chocolatey stuff is certainly a motivator, isn’t it, David?"
"Yes, it is, Mark, and that makes for a much more interesting race. The last time they ran the Hungry-Not Hungry Stakes, you remember they used regular rat chow for the lure, and it was a huge disappointment for the fans – the Not Hungry rats never threatened in a thoroughly lackluster effort. Good change...good move by the track officials here at University Downs."
* * *
What is it about certain food items that makes rats, and people, eager to eat them – even when, in ordinary terms, Not Hungry? And why does this matter?
We'll be right back with the answers, but first, the housekeeping:
WHEE (Weight, Health, Eating and Exercise) is a community support diary for Kossacks who are currently or planning to start losing, gaining or maintaining their weight through diet and exercise or fitness. Any supportive comments, suggestions or positive distractions are appreciated. If you are working on your weight or fitness, please -- join us! You can also click the WHEE tag to view all diaries.
Here's the current WHEE diary schedule, so far as I know. Please volunteer...More participants, more fun! Comment to tip jar and I'll add you wherever you wish.
September 15
Tues PM - ???
September 16
Weds AM - Edward Spurlock
Weds PM - ???
September 17
Thurs AM - Ed G
Thurs PM - ???
September 18
Fri AM - ???
Fri PM - ???
September 19
Sat AM - ???
Sat PM - Edward Spurlock (Kessler, Ch. 7)
September 20
Sun AM - louisev - Turtle Diary
Sun PM - ???
September 21
Mon AM - NC Dem
Mon PM - ???
September 22
Tues AM - Clio2 (Kessler, Ch. 8)
Tues PM - ???
Kessler started research for his book with intersecting questions: Why have Americans, statistically, recently become so fat? And why was he, Kessler, struggling with his weight as well? Introspection, and interviews, strongly suggested that for many, it is all related to a feeling of lost control over the frequent decisions we have to make about about eating, or not eating.
Kessler has hammered it into us for five previous chapters: it has to do with the types of foods that are regularly presented to us for consumption. Ubiquitous, often cheap foods that somehow, are able to overcome our natural appetite controls. (Edward Spurlock's diary on Ch. 5 gives links to previous read-a-thon installments.)
Some types of foods people eat mainly just because they are Hungry: our bodies are calling for fuel and building materials. When those needs are met, we find it natural to stop eating. Think for instance (though it varies with the person)...unsweetened oatmeal with milk. Black beans and rice. Tomato juice. Ripe apples. Scrambled eggs. Such foods can taste delicious when we're Hungry, but there's no temptation to gorge. On a regimen of such foods, we tend to maintain a stable weight.
Others edibles we consume not primarily out of need, but for the sensory reward they offer. Think for instance (depending on the person)...our favorite type of ice cream. General Tso's Chicken. Cheddar cheese straws (one of my Waterloos). Of course, we may consume such "hyperpalatable" items when we are Hungry. But many of us also feel pulled to eat them when we are Not Hungry. Moreover, at the point our needs are met, many of us don’t find it natural or easy to stop eating. We lose control. We overeat. We gain.
What gives a food the power to shatter many people's inbuilt appetite control? According to Kessler, the key is sugar, fat and salt -- rarely one alone, but rather in potent and well-calibrated combinations.
In Ch. 6, if anyone is not convinced, Kessler presents the message from yet another angle. Previously, we met rats who would cross the rodent's equivalent of a mine field for Froot Loops and rats who got fat when offered a "supermarket diet" of "sweetened condensed milk, chocolate chip cookies, salami, cheese, bananas, marshmallows, milk chocolate and peanut butter." In Ch. 6 the rats -- and mice -- get workouts designed to provide more evidence.
As described (with embellishments), rat races showed that even Not Hungry rats will run for the tasty chocolate cereal nearly as fast as Hungry rats, and they will consume almost as much. For regular rat chow, Hungry rats would run, but Not Hungry rats merely yawned.
With the help of more rat (and mouse) workouts, Kessler aims to demonstrate that elevated levels of fat, salt and sugar do indeed motivate increased consumption...that in the full, technical sense they are indeed strongly reinforcing.
Reinforcement
occurs when an event following a response causes an increase in the probability of that response occurring in the future. Response strength can be assessed by measures such as the frequency with which the response is made (for example, a pigeon may peck a key more times in the session), or the speed with which it is made (for example, a rat may run a maze faster). The environment change contingent upon the response is called a reinforcer...[A]ctivities, foods or items which are generally considered pleasant or enjoyable may not necessarily be reinforcing; they can only be considered so if the behavior that immediately precedes the potential reinforcer increases in similar future situations.
His first criterion: Are they willing to work to obtain it?
Another lab contribution to the rodent Olympics challenged rats to press a lever for different strength sugar solutions. The catch: each reward required more lever presses than the one before. At what point would the rats decide, "Hey, this is getting to be too much work," and stop pressing the lever? That, theoretically, would index how reinforcing the sugar solution was...or in anthropomorphic terms, how powerful a craving it aroused in the animals.
Answers (rounded):
No sucrose: 5 rewards, the last requiring 16 lever presses
10% sucrose: 6 rewards, the last requiring 23 lever presses
20% sucrose: 8 rewards, the last requiring 44 lever presses
(Interest dropped off slightly at 30% sucrose, at 7 rewards with the last requiring about 32 lever presses. Rats have a bliss point different from ours...people tend to prefer about 10% sucrose solutions.)
Mice got the nose-poke challenge: how many times would they thrust their noses into a hole to get different liquids – again on a steepening effort curve?
For a 10% corn-oil solution, mice would work until they earned 12 rewards, with the last requiring 50 nose-pokes. But for a combination of fat and sugar? A whopping 14 rewards, demanding 77 nose-pokes to finally obtain that 14th delectable mouthful.
That’s a strong reinforcer...according to the researcher interviewed by Kessler, a mouse's giving-up point for the sugar-and-fat combo worked out only "slightly lower" than for cocaine.
Kessler also reports that in mixtures,
Fat is also reinforcing, but calorie for calorie, sucrose is the dominant factor.
Salt also can be reinforcing.
And BTW, what was that powerfully reinforcing sugar-fat combo liquid that persuaded mice to jam their noses into a little hole 77 times for a 14th sip?
Why, I've drunk it myself...it's called Ensure®, a product that advertises, "Complete balanced nutrition...as part of a healthy diet."
I don't happen to have a can around, but according to one source, the ingredients consist of:
Water, sugar (sucrose), corn syrup, maltodextrin (corn), calcium caseinate, high-oleic safflower oil, canola oil, soy protein isolate, whey protein concentrate, corn oil, calcium phosphate tribasic, potassium citrate, magnesium phosphate dibasic, natural and artificial flavor, soy lecithin, sodium citrate, magnesium chloride, salt (sodium chloride), carrageenan, choline chloride, potassium chloride, ascorbic acid, ferrous sulfate, alpha-tocopheryl acetate, zinc sulfate, niacinamide, calcium pantothenate, manganese sulfate, cupric sulfate, vitamin A palmitate, thiamine chloride hydrochloride, pyridoxine hydrochloride, riboflavin, folic acid, chromium chloride, biotin, sodium molybdate, sodium selenate, potassium iodide, phylloquinone, vitamin D3 and cyanocobalamin. [Sugars bolded, fats in bold italic.]
It comes in different formulas. This site reviewed Ensure® Plus liquid nitrition and found it provided 355 calories per cup.
The good: This food is very low in Cholesterol. It is also a good source of Vitamin C and Manganese.
The bad: A large portion of the calories in this food come from sugars.
The detailed information on the site shows that the liquid contains, per cup, 50 grams of sugar, no complex carbohydrates, 11 grams of fat, and 13 grams protein. That's 56% of calories from sugar, 29% from fat and 15% from protein.
I am now not surprised to remember how, when at one time I tried to use this -- or a similar product -- as part of a diet scheme, it failed because I found the smooth, sweet liquid rather addictive. It was tasty but not filling, and a single can at lunchtime, too often, led to another in the afternoon.
However, if anyone is interested, the Ensure® website offers a free six-pack to anyone who takes the "Twenty-Four Day Challenge" as well as recipes including Cheddar Turkey Quiche (made with Homemade Vanilla Ensure®) and Dark Chocolate Waffles:
1-1/2 cups Bisquick Heart Smart® or low-fat waffle/pancake baking mix
1/2 cup whole wheat flour
1/3 cup dark natural unsweetened cocoa
1/4 cup sugar
1 large egg
1 cup (8 ounces) Ensure® Rich Dark Chocolate Shake
1/2 cup skim milk
1 teaspoon pure vanilla extract
1 cup non-fat whipped dairy topping
2 cups mixed berries
Confectioners’ sugar, optional for dusting
Now before you get all huffy, this contains only 220 calories per serving. Of course, it's also true that a serving is 1 waffle, and this recipe makes 8 waffles, so you will probably end up with more than one waffle per person unless you have a very large family, and I can't help noticing that if you make 8 waffles, each waffle ends up containing only 1 ounce of the original product, so a person might be forgiven for wondering, what is the point?
I seem to have strayed pretty far off the racecourse, so to head for the finish, Kessler learned that sugar and fat additionally can demonstrate their role as reinforcers by lending their power to a secondary reinforcer, which
has acquired its function as a reinforcer after pairing with a stimulus which functions as a reinforcer. This stimulus may be a primary reinforcer or another conditioned reinforcer (such as money). An example of a secondary reinforcer would be the sound from a clicker, as used in clicker training.
In this case, rats would tend to hang around in areas where they previously got either Froot Loops or Cheetos, even when the rats didn't find anything particularly attractive about those locations before the treats.
What else besides the concentration of luscious fat, salt and/or sugar goes into motivating rats to behave like participants in an eating contest?
According to Kessler:
Quantity: if there's more, they'll eat it. Environmental stimulation, like a light or sound that consistently goes with the reward. Variety among foods, as in the "supermarket diet," and within foods, the layering and loading -- as we read in Ch. 4 -- plus "dynamic contrast" incorporating different sensory experinces such as smooth and crunchy, cold and warm, sour and sweet.
Not everyone reacts alike, Kessler reminds us in closing.
But for some of us, the same reinforcers that can manipulate rats to overeat in the laboratory may make us feel like hapless prey when those impulses get us in their claws.