Lecture 9A: Chapter 9

FN 225: Nutrition
Noy Rathakette, Ph.D.
Health Professions Division
Lane Community College
Eugene, Oregon

ADDITIONS / CLARIFICATIONS

REVIEW for Exam 4 page 114 in your packet-

When it asks about KETONES, look at what it says on page 50 in your packet. For a refresher, you might review Lecture 4B (scroll about halfway down to

IV In the Body: Glucose As Fuel

D. Deficiencies of Glucose

We will discuss LACTIC ACID during Week 10.

FORUM for Week 9:

How would you answer the question halfway down page 115 in your packet:

In your own words, what is meant by the statement "carbohydrates spare protein"?
Do you find that the Set-Point Theory applies to your weight?
What do you think of the 4 parts of "The Nondiet Approach" described on page 120 in your packet?
Look at the REVIEW for Exam 4 page 114 in packet.

The Online Review Quiz in Week 10 will ask questions from this REVIEW SHEET.

Do you have any questions?
Someday I would like to do a slide show with the possible title of Never, Never, Never Stop Moving. Do you have any photos you could give me permission to use of people of all ages being active?

If you do, you can attach them in your FORUM posting.

LECTURE 9A: Chapter 9- Energy Balance & Healthy Body Weight

This is a birthday card someone gave me. I hope it makes you chuckle.

First consider the major headings of this lecture:

I Energy Balance: energy in = energy out
II Two parts of Energy Expenditure: BMR & Voluntary Activity
III How the brain and nerves get energy during a fast
IV How the muscles get energy during a low carbohydrate diet
V Body Weight vs Body Fatness
VI The Mystery of Obesity: Inside the body causes
VII The Mystery of Obesity: Outside the body causes
VIII Do Extra Pounds Come from Too Much Food or Do They Come From Too Little Exercise?
IX Possible Causes of Eating Disorders (especially anorexia)
X Do's for Family Members
XI Top Ten Reasons to Give Up Dieting

Now use the following information for pages 115-117 in your packet.

I Energy Balance: energy in = energy out

A. Definition of a kcalorie (commonly called calorie)

A unit of energy (heat). It's the amount of heat energy needed to raise the temperature of one kilogram (kg, about a quart) of water one degree Celsius.

To help make clear that calories are units of energy (heat), watch this short Video Clip.

It will help you answer a Study Question about how long the walnut burns.

Video Clip: Burning A Walnut

If the movie isn't showing up on your computer, you may not have the latest version of QuickTime on your computer. Click here to download the newest version of Quick Time.

The Video Clips are best viewed with Safari or Internet Explorer as your browser. I don't understand why, but Firefox does NOT work.

(The sound is low at the beginning of this clip and then it gets louder.)

In addition to burning a walnut, the Video Clip shows a tablet of vitamin C burning.

What you saw dripping was probably what was used to help the tablet stick together. The tablet would have totally burned up if given enough time.

In the first week of this class, we talked about how vitamins are organic. This means they have carbon-to-carbon bonds that can be broken apart to release energy, which is what happens when you put a flame to the vitamin C tablet. But we don't "burn" vitamin C in our body because we don't make enzymes to do it. You can think of enzymes as sort of like a flame.

Let's consider the calories in an apple.

Babs, a kindergarten teacher, might say this apple has about 60 calories.

Dennis, a physics teacher at LCC would say it has about 60,000 calories.

Babs is talking about the common use of the term and Dennis of the scientific definition.

Actually, an apple has about 60 kilocalories or 60 capital "C" Calories.

B. If you eat 3500 more calories in a week than your body needs,

you could gain one pound.

II Two parts of Energy Expenditure

The two biggest parts of the body's Energy Expenditure are BMR and Voluntary Activity.

A. BMR (Basal Metabolic Rate)

By definition, this is the energy expended by the body for its activities when at rest after 12 hours of not eating.

Examples of activities that make up your BMR are activities your body needs to do just to stay alive when you're not eating and at rest (and awake), like:

breathing in
breathing out
heart beating
kidneys filtering waste
liver detoxifying
temperature regulation

The Basal Metabolic Rate does NOT include the activities of the digestive system.

A male's BMR generally higher than a female's because a male body generally has a higher percentage of lean body mass than a female body. A female body is made to have a higher percentage of body fat because of reproductive needs. Of course there are exceptions. A female can surpass a male if her physical conditioning is more regular.

B. Voluntary activity is the other important way the body expends energy.

Examples would be irregular activities like dashing to class or regular activities like lifting very heavy weights or swimming.

If a person is sedentary or moderately active, BMR is the body's largest energy expenditure. A sedentary person might need about 1800 calories in a day, with about 1200 of them being for the BMR.

An accurate way to measure energy expenditure is to measure oxygen use, since oxygen is needed to complete the Krebs cycle.

III How the brain and nerves get energy during a fast

A. During the 1st day of not eating your brain and nerves get energy from glycogen in your liver.

Your brain isn't set up to get energy from the glycogen in muscles. Glycogen in a muscles can only be used there in that muscle.

The body has a total of about a pound of glycogen in it. About 3-4 pounds of water is wrapped around that pound of glycogen. On a fast or a low carbohydrate diet, you lose that pound of glycogen because it is being broken down to provide glucose for the brain.

On a fast or a low carbohydrate diet, when you lose that pound of glycogen, you also lose the 3-4 pounds of water is wrapped around it. So you would lose 4-5 pounds during the first day or 2 of a fast.

This is why low carbohydrate diets are so tempting. Low carbohydrate diets do work to provide rapid and dramatic weight loss. The problem is that most of that weight is water and it's a temporary weight loss. As soon as you eat foods with carbohydrate (which your body will drive you to do since the brain needs glucose), the glycogen will come back, as will the water that wraps around that glycogen.

Your body is not happy being deprived of carbohydrate because it wants glucose for the brain and fat can not be turned into a significant amount of glucose. If you are not eating enough whole foods with starch and sugar, your body has to change some of its proteins into glucose. Your body doesn't have a reserve of proteins. Those proteins would come from the necessary protein of muscles, enzymes, antibodies, etc.

B. During the 2nd day, protein in muscles & other places gets rearranged into glucose.

This decreases the amount of lean tissue in the body.

If this kept happening, the body could last only about ten days.

Body fat cannot be rearranged into glucose in any significant amount,

Regarding what is meant by the statement "carbohydrates spare protein", this will be discussed in this week's FORUM.

C. After 2 weeks of fasting, the brain has learned to use ketones for about 1/2 of its energy needs, but the other half still comes from protein in muscles & other places (unless you're eating lots of protein).

Ketones come from fatty acids fragments. They are made when there is a lack of glucose in cells so that the Krebs cycle can't start. Without the Krebs cycle, fatty acid fragments can't go through the Krebs cycle and instead get made into ketones. Can you see, from the image above, which you have in your packet on page 51, how that happens?

Two examples of situations that might lead to ketosis are

starvation from poverty or anorexia or
uncontrolled diabetes where there is not enough insulin to help glucose get into cells.

If there is not enough glucose in cells, not enough of the Krebs cycle can happen so ketones accumulate.

After about 2 weeks of fasting or a very low carbohydrate diet, the body's rate of lean tissue loss goes down because the brain has "learned" to use ketones for about 1/2 of its energy needs (as the Lecture says just above).

By "learned", I mean that, the body has begun making enzymes to help the brain use ketones. But the other half of the brain's energy still comes from protein in muscles & other places (unless you're eating lots of protein). Someone fasting for weeks at a time can still die from loss of essential protein tissue, even if they still have fat reserves.

Now go to page 113 of your packet and fill in the the part of question #1 about ketones.

IV Muscles and Fasting

In addition to glucose, the muscles get energy during a low carbohydrate diet from fat in the body or fat in the diet.

But they still use up their protein tissue to provide glucose for the brain.

We spend so much time in this class talking about how the brain needs glucose, students sometimes forget that there is another segment of the body (the muscles) that CAN use fat.

V Body Composition
(Body Weight vs Body Fatness)

A. The Body Mass Index (BMI) may reflect amount of fat but not the location of fat. The BMI also doesn't reflect how much of the weight is muscle.

Using just the BMI, at the time of this photo, Michael Jordan would have been considered obese.

B. Some Ways to Measure Body Composition:

DEXA scan. Although I don't know who this is, it is what I had done to check my bone status. Although it is the most accurate way to measure body composition, it is also very expensive and is usually just done in medical settings.
Underwater weighing. Next to a DEXA Scan, underwater weighing is the most accurate way to measure body composition. This is based on the principle that fat "floats".

A person is first weighed. They then exhale as much air as possible and are immersed under water for 10 to 15 seconds for an underwater weight measurement to be taken. The difference is their lean (muscle and bone) body mass.

This procedure is repeated 7 to 10 times. Total test procedures may require 45 minutes to one hour.
Fatfold test. Skinfold calipers are another way to measure body composition, but they're not considered accurate because it's difficult for 2 different people to pinch and squeeze the same way. A suitable use is for one person to do the measuring, then the SAME person do it after 3 months or so to see if there's been a change.

(Notice the Gray's Anatomy textbook.)
Bioelectrical impedance. Only lean tissue and water conduct electricity. The fat does not.

Above is hand-held device for measuring body composition using bioelectrical impedance.

This is scale you can stand on and measure body composition using bioelectrical impedance. Students have told me that there are much cheaper ones available, but I'm not sure of their accuracy.
"Bod Pod". This is a fairly new way of measuring body composition called a and the one pictured below is at the UO Treatment Center beside Autzen Stadium.

While a person sits inside the enclosure, a rapidly vibrating diaphragm in the wall of the test chamber produces small changes in air pressure between it and an adjoining reference chamber.

The changes in air pressure can be used to determine the amount of air the person displaces in the test chamber. In turn, that measurement leads to an estimation of the person’s body volume, corrected for the volume of air in the lungs at the time of the measurement.

Then, taking the person’s body mass (obtained by a scale) and dividing it by the person’s body volume, the body density is determined. With that, a person’s percent body fat can be calculated.

VI The Mystery of Obesity: Inside the body causes

There is considerable proof that much obesity is genetically based. Partly using studies of twins separated at birth and raised in two different households, numbers such as these have been estimated:

o If 1 parent is obese, there is 60% chance that the child will be heavy.
o If 2 parents are obese, there is 90% chance that the child will be heavy

HOW GENES MIGHT PLAY A ROLE:

1. There could be genetic variations in perceptions of hunger and appetite.

As mentioned before, hunger is the physical need to eat. Genes in fat cells direct the making of ghrelin, a peptide hormone produced by stomach and small intestinal cells cells. It is thought to increase feelings of hunger in order to stimulate eating.

Appetite is the psychological desire to eat creating satiety (feeling full). Genes in fat cells direct the making of leptin, also a peptide hormone, but one that is produced by adipose (fat) cells. It plays a role in body weight regulation by acting on the hypothalamus to suppress appetite and burn fat stored in adipose tissue.

Perhaps the brain cells of obese people ignore these hormones, just as some diabetics' cells (Type II diabetics) ignore insulin.

Eve Van Cauter, an endocrinologist at the University of Chicago who is shown above, calls ghrelin and leptin the “yin and yang" of eating regulation.

In experiments by Van Cauter and others, sleep-deprived adults produced more ghrelin, a hormone that promotes hunger, and less leptin, a hormone that signals fullness.

2. Genes could also produce enzyme variations.

The more your genes direct the making of lipoprotein lipase enzyme (LPL), the more easily fat cells store fat.

As page 326 in the text says, LPL is "an enzyme mounted on the surface of fat cells that splits triglycerides in the blood into fatty acids and glycerol to be absorbed into the cells for reassembly and storage".

3. Genes regulate thermogenesis, sometimes called the thermic effect of food (TEF). Some people's genes may direct the expenditure of a lot of energy in thermogenesis, producing abundant heat without performing any useful work.

There could be less of a TEF happening in obese people.

If you were a hunter-gatherer who lived in a feast & famine situation, would you like to have a high TEF?

The 11th edition of our text has an addition to Table 9.4 ("Selected Theories of Metabolic Causes of Obesity"). The text calls this theory "Fetal programming theory" and here's what the text says:

The children of mothers who either starved or were obese during their pregnancies more often grew to be overweight or obese themselves. An energy-lean or energy-rich prenatal environment may influence fetal genetic expression for enzymes involved in energy metabolism: the underfed fetus adapts by producing more energy-conserving metabolic systems; the richly supplied fetus may adapt by producing more fat-storing enzymes and cells.

The following is a very interesting article that describes some epidemiological studies as well as some laboratory studies exploring this idea: Small and Thin: The Controversy over the fetal origins of adult health, Stephen S. Hall, New Yorker; November 19, 2007.

This past year I've heard of a new area of genetic research that is being called "epigenetics" and it refers to the way fetal environmental factors may produce permanent changes in the expression of genes.

I'm a bit nervous that this research might lead some experts to suggest restrictive diets in order to create certain "environmental factors". Chapter 9 as well as the lectures during Week 9 will present some of the dangers of restrictive diets.

I think a more important lesson to take from this fetal programming theory is the importance of including and enjoying in the diet a variety of whole foods as well as the importance of not over-doing or under-doing portion sizes.

This is definitely easier said than done. Our genetics, our past life experiences and our current life situations all affect our food choices (as well as our exercise patterns). If you'd like some practical ideas about food choices, you might want to consider taking the online LCC class FN 230: Family Food and Nutrition.

VII The Mystery of Obesity: Outside the body causes

A. Lack of Exercise

There are all sorts of reasons why we're getting less exercise these days. One of them is the lack of PE classes in schools. They've been a casualty of

decreased school funding and
the increasing pressure for schools to focus on academics so students score well on state-wide academic tests.

B. TV. Nutritional problems with excess TV watching:

Although some people work out when watching TV, many of us are not moving much, so it takes away from the hours in the day when we're moving.

And TV can have what I call the "zombie effect". Two of the children in the photo above have parents who were LCC nutrition faculty at the time (yes, one of them is my daughter in about 1988) and watching TV turned them into "zombies".

Research has shown that while watching TV, BMR falls even lowers that just sitting around when you're not watching TV.
People often mindlessly snack when they're watching TV. Since they're not really paying attention to what they eat, they may eat more than they need to be satisfied.
Many TV ads are for highly processed and high calorie foods and the ads make you want the food.
Many of the actors and actresses on TV have unrealistic body shapes which might encourage eating disorders.

C. External Cues.

These are all of the sight, sound and smell cues in our environment that encourage us to overeat.

Foods high in sugar are especially tempting and take the least energy to digest. Foods high in fat are also very tempting. They take a lot of time to digest, but they may not satisfy us because they don't take up much room in our stomach.

D. Some people overeat because of

1.    Habit
2.    Stress
3.    Because they're tired or
4.    Because they're bored

You're asked a Study Question about whether any of these apply to you.

E. (This topic might be better in a different section.) Alcohol can encourage fat storage.

This is something I want to learn more about. As page 95 in the text says, upon exposure to alcohol, the liver speeds up its synthesis of fatty acids.

F. Weight Cycling is the on again-off again dieting that some people experience.

We get all sorts of cues in our culture that dieting is a good thing. But weight loss diets seldom are successful in achieving long-term weight loss. Instead, what can happen after successful weight loss is that the person begins overeating, gaining more weight that what they weighed before the diet.

G. (This topic might also be better in a different section.) The Set-Point Theory is the idea that we all have an approximate weight our body wants and it's very difficult to get more than 10 pounds above that weight or more than 10 pounds below that weight.

Add this to the bottom of page 117 as an additional possible "outside the body" explanation for the Mystery of Obesity:

H. Food Insecurity

This is a condition in which people lack basic food intake at all times to provide them with the energy and nutrients for fully productive lives.

A number of studies have shown that although food insecurity leads to below minimum calorie intakes, many poor children are still overweight. One article suggested two possible explanations for this paradox.

CYCLES OF FASTING & BINGING:

Following periods of fasting, the liver is primed to store fat.

Then when food becomes available again the person may binge eat. The rapid blood sugar rise can spike insulin levels and insulin promotes fat storage. This can be accentuated when the binging precedes bedtime.
Inadequate intake of MICRONUTRIENTS (vitamins & minerals). For example, "Animal, human being and population-based studies have recently shown that for any given level of energy expenditure and energy intake, a low-calcium diet increased adipose tissue and a high-calcium diet had the opposite effect."

"Diabetes Risk, Low Fitness, and Energy Insufficiency Levels among Children from Poor Families",
Roberto P et al,
Journal of the American Dietetic Association, November, 2008.

In a USDA report released in November, 2008, Oregon was ranked the third hungriest state in the nation. The Dining Room, which FOOD for Lane County runs to provide free meals to all comers four week nights a week, is serving about 350 people a night as of November, 2008. The preceding year, it was 250 people each night.

The Dining Room has five employees, like Amanda, shown below.

Each month, about 250 volunteers help out at the Dining Room, like the two below.

I wonder if volunteers also did the mural outside, just a portion of which is shown below.

REACHING OUT A HAND: FOOD for Lane County’s Dining Room tries to make a difference, By Laura Ruggeri, The Register-Guard, November 25, 2008.

VIII Do Extra Pounds Come from Too Much Food or
Do They Come From Too Little Exercise?

Much of the following information is from the Tufts University Health & Nutrition Letter, April 2003.

Evidence from surveys suggests that people have more or less remained at the same level of sedentary living since 1985.

But average daily calorie intake has gone up 400 calories.

What about our eating habits has changed during that time?

1. INCREASED DIETARY VARIETY.

In 1973, there were 100 new bakery products introduced into the marketplace.
In 1993, there were 1500 new bakery products introduced into the marketplace.

2. A GLUT OF LIQUID CALORIES.

Between 1977 and 1998, soft drink consumption increased by 60%.

According to research at Purdue University in Indiana:

When you eat 100 extra calories, you reduce your calorie consumption by almost 100 calories later in the day.

When you drink 100 extra calories, you eat at least as much later as if you hadn't drunk anything, so you're just adding 100 calories--or more--to your total.

This link gives information about the calories in different Starbucks' beverages.

Notice the drop-down menu of serving size choices.
http://www.starbucks.com/retail/nutrition_beverages.asp

3. GROWING PORTION SIZES.

And research has shown that people consume more when served larger portions.

Remember these images from earlier in the term?

Your Plate Is Bigger Than Your Stomach, By David Leonhardt, The New York Times, May 2, 2007. This article discusses the 2006 book “Mindless Eating: Why We Eat More Than We Think”, written by Brian Wansink, a Cornell professor who has spent his career doing experiments about the psychology of eating.

An example from the book- Wansink (pictured above) and his research assistants carried huge bags of five-day-old popcorn into a Chicago theater during an afternoon showing of the movie Payback. They filled medium-sized and large-sized “bigger-than-your-head” buckets with the popcorn, then gave it away for free.

The researchers measured how much popcorn each ate. Yes, people ate the popcorn. And the people who had larger containers ate an average of 173 calories worth more.

I think Brian Wansink is a very interesting and unpredictable person.

Click here for his website.

The 2007 Ig Nobel for nutrition went to him for his "bottomless bowl of soup". The Ig Nobel awards are prizes for quirky, funny and sometimes legitimate scientific achievements. Mark Pratt, Associated Press, Oct. 4, 2007

Prof. Brian Wansink Chosen to Lead Nutrition Center at USDA (U.S. Department of Agriculture Center for Nutrition Policy and Promotion), The Cornell Daily Sun, Nikhita Parandekar, November 29, 2007.

4. TOO DELICIOUS.

Good-tasting, interesting meals may induce hunger sooner than more basic meals.

5. SNACKING.

Between the 1970s and mid 1990s, we've increased the number of snacks we have by 50% AND we're choosing bigger portions and higher calorie snacks.

6. EATING OUT.

People who ate out at least 13 times a month consumed an average of 32% more calories than those who ate out fewer than 5 times a month.

How can you apply these findings to your own eating habits?

IX Possible Causes
[maybe "contributors" would be a better word]
of Eating Disorders (especially anorexia)

As we seek to understand another's problems, it's tempting to blame someone (like the person or the parents) and comfort ourselves that the same thing won't happen to us if we just don't do what the other person is doing wrong. But in addition to not being helpful, that blame can make matters worse instead of better. It is more likely that a supportive understanding can more quickly lead to the help that is usually necessary for recovery.

A friend saw a bumper sticker once that said something like “Children don't choose anorexia and parents don't cause it.” What other people do can contribute to eating disorders, but other people are not the cause. A person with several of the following contributing factors doesn't mean they have to accept the inevitable and adopt a “victim” mentality. But if it does happen, quickly getting help can enable them to manage the disorder so it can move to the background of their life.

These are my ideas about contributing factors.

Genetics. Eating disorders run in families and it's easy to assume the family environment led to the problem. Recent studies of twins, presumably raised in the same environment, are finding a clear genetic link. “In a large study comparing the number of identical twins who had anorexia with the significantly smaller number of fraternal twins who had it, scientists concluded that more than 50 percent of the risk for developing the disorder could be attributed to an individual's genetic makeup. A few small studies have even isolated a specific area on the human genome where some of the mutations that may influence anorexia exist, and now a five-year, $10 million NIMH study is underway to further pinpoint the locations of those genes.” (Tyre, Newsweek)

Twin studies have also looked at bulimia. “Women with bulimic or anorexic female relatives are four to five times more likely to develop the disorder, and twin studies reveal that the genetic risk factor may be as high as 58 percent.” (Psychology Today)

Perhaps genes help create a brain chemistry that can lead people to use starvation (or over-eating) as a way to control anxiety. Serotonin is a chemical messenger in the brain made from the essential amino acid tryptophan and it affects emotions, behavior, and thought. Normal levels of serotonin are believed to be associated with feelings of well-being. Both low and high levels of serotonin may be associated with certain mental health disorders. Both starvation and over-eating could be attempts to return brain serotonin levels to normal. It has been suggested that the brain of a person with anorexia may have increased serotonin activity.
Control Issues. Most of us have a desire to control what's happening in our lives, and in varying ways. When we feel ourselves losing that control, some can temporarily “go with the flow” until they can find satisfying ways to re-gain it. Others may lash out with violent behavior or seek escape with drugs or alcohol. Still others may decide to use not eating or over-eating to feel a measure of control. All of these ways of seeking control can have a genetic basis, as evidenced by the incidence of alcoholism in families.
Culture. Our culture places tremendous value on narrow aspects of image such as thinness. Rather than pursuing their unique interests and goals, many who don't fit this image become preoccupied and depressed if they don't naturally fit this image. When they lose weight, some may tell them how good they look. This gives the message that they didn't look good before and they can feel they probably don't look good yet. So they keep dieting and for some reason we don't understand, the eyes of a person with anorexia see a fat person in the mirror, even when they're dangerously underweight.
Stressful/Traumatic Events. Examples I've seen include a teenager whose boyfriend teased her because of her “thunder thighs” and broke up with her, parents who insisted on dieting because their child was being taunted, a parent's serious illness, the stress of college applications, a messy divorce at age 40 and a high-school exchange living situation in Mexico where the family was domineering and demanding. It's impossible to avoid stressful and traumatic events, but empathy regarding the impact of life experiences can be very helpful.

X Do's for Family Members & Friends of People with Eating Disorders
(A list is in your packet.)

So what should you do if someone you care about shows signs of an eating disorder? Treatment seems simple- either eat if the problem is under-eating or don't eat if the problem is over-eating. But treating a person with an eating disorder as if the treatment is simple can have an opposite-of-the-desired effect and instead make the problem worse instead of better. One term, a student told me “I developed an eating disorder a couple of years ago at almost 40 years old during my divorce and the people around me chose to try to discipline it out of me.” She told me that attitude did not help her as she struggled to recover.

XI Top Ten Reasons to Give Up Dieting
(A list is in your packet.)

The Nondiet Approach (This list, which is in your packet, is from the book below.)

Total health enhancement and well-being, rather than weight loss or achieving a specific "ideal weight."
Self-acceptance and respect for the diversity of healthy, beautiful bodies, rather than the pursuit of an idealized weight at any cost.
The pleasure of eating well, based on internal cues of hunger and satiety, rather than on external food plans or diets.
The joy of movement, encouraging all physical activities rather than prescribing a specific routine of regimented exercise.

End of Lecture 9A