chapter 4
Diverticula
are abnormally bulging pockets in the colon wall. These pockets can entrap feces and become painfully infected and inflamed, requiring hospitalization, antibiotic therapy, or surgery.
complex carbohydrates= starch and fiber
long chains of sugar units arranged to form starch or fiber; also called polysaccharides. -Complex carbohydrates contain chains of glucose - a simple sugar.
According to the article, researchers estimated that people who eat a(n) __________diet have the greatest risk of premature death.
low carbs
Digestible carbohydrates are absorbed as_______ through the small intestinal wall and are delivered to the liver, which releases ______ into the bloodstream.
monosaccharides; glucose
Glucagon increases blood glucose levels by stimulating what?
liver cells to break down liver glycogen
Digestible carbohydrates
together with fats and protein, add bulk to foods and provide energy and other benefits for the body
The fiber-rich portion of the wheat kernel is the bran layer.
true
foods rich in soluble fiber lower blood cholesterol.
true
How Is Glucose Regulated in the Body?
two safeguard activities: Removing/siphoning excess glucose from blood•Replenishing diminished glucose 2 hormones that are critical to this process:: insulin -Stimulates glucose storage as glycogen •Glucagon•Helps release glucose from storage Glycogen storage is limited (~2000 cal in the liver) but fat storage is nearly unlimited at over 70,000 calories Muscles hoard two-thirds of the body's total glycogen•The liver stores the remainder and is generous with its glycogen releasing glucose into the bloodstream for the brain or other tissues when the supply runs low
diabetes
, blood glucose rises after a meal and remains above normal because insulin is either inadequate or ineffective. Abnormally high blood glucose is a characteristic of two main types of diabetes.
which of the following appears to be the healthiest amount of carbohydrates in the diet?
50-55% of calories
sucrose
=White Sugar•Raw sugar is made from sugar cane and sugar beets. This raw sugar must be further refined for human consumption.•White sugar provides virtually no nutrients for its 16 kcalories/teaspoon.
milk and milk products
A cup of milk or plain yogurt is a generous contributor of carbohydrate, donating about 12 grams. Cottage cheese provides about 6 grams of carbohydrate per cup, but most other cheeses contain little, if any, carbohydrate. These foods also contribute high-quality protein (a point in their favor), as well as several important vitamins and minerals. Calcium-fortified soy beverages (soy milk) and soy yogurts approximate the nutrients of milk, providing some amount of added calcium and 14 grams of carbohydrate. Milk and soy milk products vary in fat content, an important consideration in choosing among them. Sweetened milk and soy products contain added sugars. Butter and cream cheese, though dairy products, are not equivalent to milk because they contain little or no carbohydrate and insignificant amounts of the other nutrients important in milk. They are appropriately associated with the solid fats.
fruit
A fruit portion of cup of juice, a small banana or apple or orange, cup of canned or fresh fruit, or cup of dried fruit supplies an average of about 15 grams of carbohydrate, mostly as sugars, including the fruit sugar fructose. Fruit vary greatly in their water and fiber contents and in their sugar concentrations. Juices should contribute no more than half of a day's intake of fruit. Except for avocados and olives, which are high in healthful fats, fruit contain insignificant amounts of fat and protein.
bodies use of glucose
Basic carbohydrate unit used for energy •The body handles glucose judiciously•Maintains internal store •Tightly controls blood glucose concentration •The brain stores a tiny fraction of the total as an emergency reserve to fuel the brain for an hour or two in severe glucose deprivation
digestive tract health
Benefits of fiber: •Protects against constipation, hemorrhoids, appendicitis, and diverticulosis •Fiber feeds the intestinal bacteria that contribute to colon health. •Cellulose enlarges and softens the stools and speeds up transit.
Digestive Tract Cancers
Cancers of the colon and rectum claim tens of thousands of lives each year. The risks of these cancers are highest among people with low dietary fiber intakes, Subjects in one study who ate the most fiber (28 or more grams per day) had risks of colon and rectal cancer that were 17 percent lower than in subjects who ate the least.
The Breakdown of Glucose Yields Energy and Carbon Dioxide
Cell enzymes split the bonds between the carbon atoms in glucose, liberating the energy stored there for the cell's use. The first split yields two 3-carbon fragments. The two-way arrows mean that these fragments can also be rejoined to make glucose again. Once they are broken down further into 2-carbon fragments, however, they cannot rejoin to make glucose. The carbon atoms liberated when the bonds split are combined with oxygen and released into the air, via the lungs, as carbon dioxide. Although not shown here, water is also produced at each split.
medical nutrition therapy
Control carbohydrate intake•Amount and source •Carbohydrate recommendations•Varies with glucose tolerance and carbohydrate timing
Select the list of foods that would all rank low on the glycemic index.
Corn, strawberries, yogurt
digestion of starch: from carbs to glucose Starch and disaccharides are broken down into monosaccharides for absorption Begins in the mouth •Amylase splits starch into shorter units•Stops in the stomach•Resumes in small intestine•Resistant starch
Digestion of most starch begins in the mouth, where an enzyme in saliva mixes with food and begins to split starch into shorter units. While chewing a bite of bread, you may notice that a slightly sweet taste develops—the disaccharide maltose is being liberated from starch by the enzyme. The salivary enzyme continues to act on the starch in the bite of bread until it is pushed downward and mixed with the stomach's acid and other juices. The salivary enzyme (made of protein) is deactivated by the stomach's protein-digesting acid. With the breakdown of the salivary enzyme in the stomach, starch digestion ceases, but it resumes at full speed in the small intestine, where another starch-splitting enzyme is delivered by the pancreas. This enzyme breaks starch down into disaccharides and small polysaccharides. Other enzymes liberate monosaccharides for absorption. Most forms of starch are easily digested.
the nature of sugar
Each teaspoonful of any sweet can be assumed to supply about 16 calories and 4 grams of carbohydrate. An exception is honey, which packs more calories into each teaspoon because its crystals are dissolved in water; the dry crystals of sugar take up more space. If you use ketchup liberally, remember that each tablespoon of it contains a teaspoon of sugar. And for soft-drink users, a 12-ounce can of sugar-sweetened cola contains at least 8 teaspoons of added sugar.
digestion of sugars
Enzymes in your intestinal cells must split the disaccharides into separate monosaccharides so that they can enter the bloodstream. The blood delivers all products of digestion first to the liver, which possesses enzymes to modify nutrients, making them useful to the body. Glucose is the monosaccharide used for energy by all the body's tissues, so the liver releases abundant glucose into the bloodstream for delivery to all of the body's cells. Galactose can be converted into glucose by the liver, adding to the body's supply. Fructose, however, is normally used for fuel by the liver or broken down to building blocks for fat or other needed molecules.
Hypoglycemia
In healthy people, blood glucose rises after eating and then gradually falls back into the normal range without attracting notice. In hypoglycemia, blood glucose drops below normal, bringing on unpleasant symptoms such as weakness, irregular heartbeats, sweating, anxiety, hunger, trembling, and, rarely, seizures and loss of consciousness. Hypoglycemia rarely occurs in healthy people, whose hormones maintain normal blood glucose concentrations. It most often happens as a consequence of poorly managed diabetes. Blood glucose can plummet with too much insulin, too much strenuous physical activity, inadequate food intake, or illness.
heart disease and stroke related to fiber
Evidence suggests that diets rich in fruit, legumes, vegetables, nuts, seeds, and whole grains—and therefore rich in fibers and other complex carbohydrates—are protective against heart disease and stroke. Such diets are also generally low in added sugars, saturated fat, and trans fat, and are high in nutrients and phytochemicals—all factors associated with a reduced risk of heart disease. Oatmeal was first to be identified among cholesterol-lowering foods. Apples, barley, carrots, and legumes are also rich in gel-forming fibers that can lower blood cholesterol. In contrast, diets high in refined grains and added sugars may push blood lipids toward elevated heart disease risks.
simply put, insulin regulates blood glucose by:
Facilitating blood glucose uptake by the muscles and adipose tissue. Stimulating glycogen synthesis in the liver.
excess fiber-Very-high-fiber all-plant diets can pose nutritional risks for people who are old or malnourished, and for young children. -Chelating agents-bind & excrete•Can overwhelm digestive system
Fiber makes food bulky and takes up space in the stomach, so a person who eats only small amounts of food at a time may not meet energy or nutrient needs when the diet presents too much high-fiber food. The malnourished, the elderly, and young children adhering to all-plant (vegan) diets are especially vulnerable to this problem. -Don't give up on high-fiber foods if they cause gas. Instead, start with small servings and gradually increase the serving size over several weeks; chew foods thoroughly to break up hard-to-digest lumps that can ferment in the intestine; and try a variety of fiber-rich foods until you find some that do not cause the problem
Healthy Weight Management
Foods rich in fibers tend to be low in fats, added sugars, and calories and can therefore help to prevent weight gain and promote weight loss by delivering less energy per bite -In addition, fibers absorb water from the digestive juices; as they swell, they create feelings of fullness and delay hunger -The opposite is certainly true of low fiber intakes: as populations eat more refined low-fiber grains and concentrated sweets, body fat stores expand.
The Need for Carbohydrates
Glucose is a critical and primary energy source -Facilitates cell-to-cell communication -Facilitates nerve and brain cell functioning •The body tissues use carbohydrate for energy and other critical functions •The brain and nerve tissues prefer carbohydrate as fuel, and red blood cells can use nothing else •Intakes of refined carbohydrates should be limited Carbohydrates have been wrongly accused of being the "fattening" ingredient of foods •For weight loss: •Control caloric contribution •Conversion into fat is inefficient •Refined sugars contain no other nutrients •Increase fiber-rich whole-food carbohydrate sources •Reduce foods high in refined grains and added sugars
splitting glucose for energy
Glucose is broken in half: •Can reassemble •Broken into smaller molecules: -Irreversible -Two pathways
What are important functions of fiber in the body?
Helps regulate blood sugar and cholesterol levels. Supports healthy bacteria in the colon. Contributes to satiety
type 1 diabetes:
In the less common type 1 diabetes, the pancreas fails to produce insulin. The immune system attacks and destroys insulin-producing cells in the pancreas as if they were foreign cells 5-10% of cases •Often juvenile type •Autoimmune disorder •Own immune system attacks pancreas •Lose ability to produce insulin •External sources of insulin•Fast-acting and long-acting forms cure: External sources of insulin needed to assist cells to take up glucose
insoluble fibers
Insoluble Fiber •Do not dissolve in water and are not easily fermented by bacteria .•Found on outer layers of whole grains, in strings of celery, or skins of corn kernels. •Help the colon eliminate wastes. "roughage" •Speeds up transit time •Bran, lettuce, celery, cucumbers, cabbage •cellulose
Which statement best defines insoluble fibers?
Insoluble fibers support digestive tract health
grains
Nutrition authorities encourage people to reduce intakes of refined grains and to make at least half of the grain choices whole grains. A slice of bread, half an English muffin, a 6-inch tortilla, cup of rice or pasta, or cup of cooked cereal provides about 15 grams of carbohydrate, mostly as starch. Ready-to-eat cereals, particularly those that children prefer, can derive over half their weight from added sugars, so consumers must read labels. -Most grain choices should also be low in solid fats and added sugar.
Oils, solid fats, and added sugars
Oils and solid fats are devoid of carbohydrate, but added sugars provide almost pure carbohydrate. Most people enjoy sweets, so it is important to learn something of their nature and to account for them in an eating pattern. -The body handles all the sugars in the same way, whatever their source.
lactose intolerance -lactase (enzyme) is deficient so lactose (milk sugar) is not split into its components in the small intestines. •Instead it travels to the colon (large intestine), where it attracts water and causes bloating and diarrhea. •In addition, intestinal bacteria ferment lactose and produce gas. •Symptoms usually occur within 30 minutes to 2 hours and clear up within 2 to 5 hours.
Persistent painful gas may herald a change in the digestive tract's ability to digest the sugar in milk, a condition known as lactose intolerance. Its cause is insufficient production of lactase, the enzyme of the small intestine that splits the disaccharide lactose into its component monosaccharides glucose and galactose, which are then absorbed. -Symptoms of Lactose Intolerance: People with lactose intolerance experience nausea, pain, diarrhea, and excessive gas upon drinking milk or eating lactose-containing products. The undigested lactose remaining in the intestine demands dilution with fluid from surrounding tissue and the bloodstream. Intestinal bacteria use the undigested lactose for their own energy, a process that produces gas and intestinal irritants. **can tolerate up fo 1 or 2 cups a milk a day
Should your glucose supplies ever fall too low, you would feel dizzy and weak. A healthy body guards against both conditions with two safeguard activities:
Siphoning off excess blood glucose into the liver and muscles for storage as glycogen and into the adipose tissue for storage as body fat. Replenishing diminished blood glucose from liver glycogen stores. -Two hormones prove critical to these processes. The hormone insulin stimulates glucose storage as glycogen, while the hormone glucagon helps release glucose from storage.
vegetables
Starchy vegetables are major contributors of starch in the diet. Just one small white or sweet potato or cup of cooked dry beans, corn, peas, plantain, or winter squash provides 15 grams of carbohydrate, as much as in a slice of bread, though as a mixture of sugars and starch. One-half cup of carrots, okra, onions, tomatoes, cooked greens, or most other nonstarchy vegetables or a cup of salad greens provides about 5 grams as a mixture of starch and sugars.
sugar digestion disaccharides- Split to monosaccharides by enzymes on small intestine lining•Travel to the liver
Sucrose and lactose from food, along with maltose and small polysaccharides freed from starch, undergo one more split to yield free monosaccharides before they are absorbed. This split is accomplished by digestive enzymes attached to the cells of the lining of the small intestine. The conversion of a bite of bread to nutrients for the body is completed when monosaccharides cross these cells and are washed away in a rush of circulating blood that carries them to the waiting liver -The absorbed carbohydrates (glucose, galactose, and fructose) travel in the bloodstream to the liver, which can convert fructose and galactose to glucose. The circulatory system transports the glucose and other products to the cells. Liver and muscle cells store circulating glucose as glycogen; all cells split glucose for energy.
sugar alcohols Sugar alcohols provide half the calories of sugars•Lower glycemic response•Safer for teeth than sugars
Sugar alcohols are manufactured sweet-tasting carbohydrates that are poorly absorbed and metabolized by the body, and so present fewer calories (0 to about 3 calories per gram) than sugars do, and they produce a lower glycemic response. Products sweetened with sugar alcohols, such as cookies, sugarless gum, hard candies, and jams and jellies, are safe in moderation, but in large amounts, they can cause gas, abdominal discomfort, and diarrhea. Sugar alcohols don't cause dental caries so they are advisedly used in chewing gums, breath mints, and other products that people keep in their mouths for a while. Other types of man-made sweeteners, the noncaloric sweeteners, sweeten foods without calories,
fiber intake-Fluid intake should increase along with fiber.
The DRI value for fiber is 14 grams per 1,000 calories, or 25 grams per day for most women and 38 grams for most men -An effective way to add fiber while lowering saturated fat is to substitute plant sources of protein (legumes) for some of the animal sources of protein (meats and cheeses) in the diet. Another way is to focus on consuming the recommended amounts of fruit, vegetables, legumes, and whole grains each day.
whole grains Dietary Guidelines for Americans recommendation-At least half of daily grains should be whole• Flour types: •Four parts to the kernel•Germ•Endosperm•Bran•Husk
The Dietary Guidelines for Americans urge everyone to make at least half of their daily grain choices whole grains, an amount equal to at least three 1-ounce servings of whole grains a day -People who take in just three daily servings of whole grains often have healthier body weights and less body fat than other people. It could be that whole grains fill up the stomach, slow down digestion, or promote longer-lasting feelings of fullness than refined grains. A higher intake of whole grains also correlates with lower risks of heart disease, type 2 diabetes, and death from all causes. Finally, people who make a habit of eating whole grains may have lower than average risks of certain cancers, particularly of the colon. It may be that the fiber, phytochemicals, or nutrients of whole grains improve body tissue health
resistant starch
The least digestible starch, called resistant starch, is technically a kind of fiber because much of it passes undigested through the small intestine into the colon where bacteria eventually ferment it. Barley, raw or chilled cooked potatoes, cooked dried beans and lentils, oatmeal, popcorn and raw corn, intact seeds and kernels, and underripe bananas all contain resistant starch.
light energy photosynthesis
The light energy becomes the chemical energy of the bonds that hold six atoms of carbon together in the sugar glucose. Glucose provides energy for the work of all the cells of the stem, roots, flowers, and fruit of the plant. -Plants do not use all of the energy stored in their sugars, so it remains available for use by the animals or human beings that consume the plants. -Through photosynthesis, plants combine carbon dioxide, water, and the sun's energy to form glucose.
Tissue Glycogen Stores
The muscles hoard two-thirds of the body's total glycogen to ensure that glucose, a critical fuel for physical activity, is available for muscular work. The brain stores a tiny fraction of the total as an emergency reserve to fuel the brain for an hour or two in severe glucose deprivation. The liver stores the remainder and is generous with its glycogen, releasing glucose into the bloodstream for the brain or other tissues when the supply runs low. Without carbohydrate from food to replenish it, the glycogen stores in the liver can be depleted in less than a day.
sugars (6 important in nutrition)
Three of these are single sugars, or monosaccharides. The other three are double sugars, or disaccharides.
blood glucose regulation
The pancreas monitors blood glucose (blue hexagons) and adjusts its concentration with two opposing hormones, insulin and glucagon. When glucose is high, the pancreas releases insulin which stimulates body tissues to take up glucose from the bloodstream. When glucose is low, it releases glucagon, which stimulates the liver to release glucose. When glucose concentration is restored to the normal range, the pancreas slows its hormone output in an elegant feedback system.
Blood Glucose Control
The soluble fibers of foods such as oats and legumes help regulate blood glucose following a carbohydrate-rich meal. Soluble fibers delay digestion of nutrients, thus slowing glucose absorption from the digestive tract. People with diabetes are urged to consume fiber-rich foods to help improve their blood glucose control.
monosaccharides-When you eat a food containing monosaccharides, you can absorb them directly into your blood
The three monosaccharides are glucose, fructose, and galactose. Fructose or fruit sugar, the intensely sweet sugar of fruit, is made by rearranging the atoms in glucose molecules. Fructose occurs naturally in fruit, in honey, and as part of table sugar. However, most fructose is consumed in sweet beverages, desserts, and other foods sweetened with added sugars. Glucose and fructose are the most common monosaccharides in nature. galactose- milk sugar, is one of two single sugars that are bound together to make up the sugar of milk. different arrangement then glucose and fructose. -Monosaccharides can be converted by the liver to other needed molecules.the
diabetes treatment
Three approaches work together: controlling carbohydrate and calorie intakes, exercising appropriately, and taking insulin injections or medications that modulate blood glucose. To control the amount of carbohydrate presented to the body at one time, it helps to eat regularly timed meals and snacks, to eat similar amounts of food at each meal and snack, and to choose nutritious foods that support a healthy body weight. Small amounts of added sugars are permissible, but nutrition suffers if the empty calories of sugar displace needed whole foods, such as fruit or vegetables, from the diet.
Explain how plants synthesize carbohydrates.
Through photosynthesis, plants combine carbon dioxide, water, and the sun's energy to form glucose. Carbohydrates are made of carbon, hydrogen, and oxygen held together by energy-containing bonds: carbo- means "carbon"; -hydrate means "water." Glucose is the most important monosaccharide in the human body. Monosaccharides can be converted by the liver to other needed molecules. Starch is the storage form of glucose in plants; it also yields glucose for the body's use. Glycogen is the storage form of glucose in the body. Fibers lend structure to plants and perform other functions. Human digestive enzymes cannot break the chemical bonds of fibers. Some fiber is susceptible to fermentation by bacteria in the colon.
The DRI Minimum Recommendation for Carbohydrate
To feed the brain, the DRI committee recommends at least 130 grams of carbohydrate a day for an average-sized person
Two Ways to Handle Excess Glucose
To handle the excess, tissues shift to burning more glucose for energy in place of fat. As a result, more fat is left to circulate in the bloodstream until it is picked up by the fat tissues and stored there. If these measures still do not accommodate all of the incoming glucose, the liver, the body's major site of nutrient metabolism, has no choice but to handle the overflow because excess glucose left circulating in the blood can harm the tissues. The liver breaks the extra glucose into smaller molecules and puts them together into a more permanent energy-storage compound—fat. Newly made fat travels in the blood to the adipose tissues and is stored there. (Fat that builds up in the liver instead can cause injury; see the Controversy.) Unlike the liver cells, which store only about 2,000 calories of glycogen, the fat cells of an average-size person store over 70,000 calories of fat, and their ability to expand their fat storage capacity over time is almost limitless.
enrichment of refined grains
U.S. Enrichment Act of 1942: refining•Iron, thiamin, riboflavin, and niacin•Folate added in 1996 •Whole grain foods superior to enriched grain foods•Vitamin B6, magnesium, zinc, fiber, and phytochemicals
which of the following diets is optimal?
a diet that includes starchy carbohydrates
glycemic index (GI)
a ranking of foods according to their potential for raising blood glucose relative to a standard food such as glucose.
What is the best example of a long-term risk associated with eating a diet that produces ketosis?
a. Vitamin deficiency b. Elevated blood cholesterol c. Loss of bone mineral
ketosis- To help supply the brain with glucose, the body breaks down its protein to make glucose and converts its fats into ketone bodies, incurring ketosis -Shift in body's metabolism •Disruption of acid-base balance
an undesirably high concentration of ketone bodies, such as acetone, in the blood or urine. -hen they reach high levels, they can disturb the normal acid-base balance, a rare but life-threatening situation. Over time, people eating diets that produce ketosis may develop deficiencies of vitamins and minerals, loss of bone minerals, elevated blood cholesterol, impaired mood, and other adverse outcomes.
glycogen
animal liver and muscle tissues store glucose in long chains that clump together to form glycogen -longer and more highly branched chains -glycogen is nearly undetectable in meats because it breaks down rapidly when the animal is slaughtered. -One glycogen molecule stores tens of thousands of glucose units nested in an easy-to-retrieve form ***Glycogen: The storage form of glucose in the body; stored in the liver (1/3) and muscles (2/3).•Muscle glycogen is only used to supply energy for muscles. •After you eat, your store carbohydrate in glycogen. •When blood glucose is low, liver glycogen releases glucose.
Carbohydrates
are ideal nutrients to meet your body's energy needs, to feed your brain and nervous system, to keep your digestive system fit, and, within calorie limits, to help fuel physical activity and keep your body lean -contain the sun's radiant energy, captured in a form that living things can use to drive the processes of life. -carbohydrates form the first link in the food chain that supports all life on earth. Carbohydrate-rich foods come almost exclusively from plants; milk is the only animal-derived food that contains significant amounts of carbohydrate. -Carbohydrates are made of carbon, hydrogen, and oxygen held together by energy-containing bonds: carbo means "carbon"; hydrate means "water."
Disaccharide- when you eat disaccharides, though, you must digest them first.
are linked pairs of single sugars. The disaccharides are lactose, maltose, and sucrose. All three contain glucose. In lactose, the milk sugar just mentioned, glucose is linked to galactose. Malt sugar, or maltose, has two glucose units. Maltose appears wherever starch is being broken down. It occurs in germinating seeds and arises during the digestion of starch in the human body. sucrose, is familiar table sugar. In sucrose, fructose and glucose are bonded together. Table sugar is obtained by refining the juice from sugar beets or sugar cane, but sucrose also occurs naturally in many vegetables and fruit. It tastes sweet because it contains the sweetest of the monosaccharides, fructose.
What Can I Eat to Make Workouts Easier?
at least an hour before your workout, eat a small snack of about 300 calories of foods rich in complex carbohydrates and drink some extra fluid
Steven's preference is that most of his carbohydrate intake comes from sources low on the glycemic index scale. What types of foods should Steven consider to include in his diet that will not spike blood glucose levels?
carrots, legumes, peaches
Ketosis is the result of too much carbohydrate in the body tissues.
false- Ketosis is the result of too little carbohydrate in the body tissues
The liver's capacity to store glycogen is virtually unlimited.
false-The liver's glycogen storage is limited to about 2,000 calories' worth
To achieve the fiber intakes that are best for you, The best fiber sources are whole foods from plants.
follow the eating patterns of the Dietary Guidelines for Americans. Choose the recommended servings of whole, nutrient-dense fruit and vegetables, make at least half the grain choices whole grains, and choose legumes several times per week. That way, you'll obtain all of the benefits that plant foods have to offer. Eating a diet of highly refined foods and adding a fiber supplement is simply not the same.
carbs are used as fuel by
fuel by the brain and central nervous system; these tissues prefer glucose, and red blood cells use glucose exclusively -Sugars also bind to the outsides of cell membranes, where they facilitate cell-to-cell communication and nerve and brain cell functioning
When blood glucose concentration rises, the pancreas secretes _______ and when blood glucose levels fall, the pancreas secretes._______
insulin; glucagon
the recommended range of total carbohydrate
intakes is from 45 to 65 percent of daily calories. This amounts to 900 to 1,300 calories of carbohydrate in a 2,000-calorie diet, but for a person needing just 1,200 calories a day, carbohydrate should provide only 540 to 780 calories.
When added sugar is consumed in excess of calorie need,
it alters blood lipids in potentially harmful ways.
The body's use of fat for fuel without the help of carbohydrate results in the production of
ketone bodies
look out for this when it says high fiber
label readers can distinguish one kind from the other by scanning the food's ingredients list for words like bran, cellulose, methylcellulose, gums, or psyllium. Such high-fiber foods may be nutritious and useful in their own way, but they cannot substitute for whole-grain foods in the diet.
fiber digestion: Fermented by bacteria in the colon
most fibers are not changed by human digestive enzymes, many of them can be fermented by the bacterial inhabitants of the human colon. The fermentation process breaks down carbohydrate components of fiber into other products, including the small fats important to the health of the colon.
The ________monitors blood glucose and adjusts its concentration with two opposing hormones, insulin and glucagon.
pancreas
how to lose weight and eat carbs
people who wish to lose fat, maintain lean tissue, and stay healthy can do no better than to attend closely to portion sizes and calorie intakes, and to design an eating plan around carbohydrate-rich fruit, legumes, vegetables, and whole grains.
starch
plant's storage form of glucose. As a plant matures, it not only provides energy for its own needs but also stores energy in its seeds for the next generation. -For the plant, starch is useful because it is an insoluble substance that will stay with the seed in the ground and nourish it until it forms shoots with leaves that can catch the sun's rays. --Packed in granules in plant's seeds
protein foods
provide almost no carbohydrate to the diet. The exceptions are nuts, which provide a little starch and fiber along with their abundant fat, and legumes (dried beans), revered by diet-watchers as high-protein, low-fat sources of both starch and fiber that can reduce feelings of hunger. Just cup of cooked beans, peas, or lentils provides 15 grams of carbohydrate, an amount equaling the richest carbohydrate sources. Among sources of fiber, legumes are peerless, providing as much as 8 grams in cup.
simple carbohydrates=sugars
sugars, including both single sugar units and linked pairs of sugar units. The basic sugar unit is a molecule containing six carbon atoms, together with oxygen and hydrogen atoms. -They are the building blocks of most sweeteners we use
protein-sparing action
the action of carbohydrate and fat in providing energy that allows protein to be used for purposes it alone can serve. -When body protein is used, it is taken from blood, organ, or muscle proteins; no surplus of protein is stored specifically for such emergencies. Protein is indispensable to body functions, and carbohydrate should be kept available precisely to prevent the use of protein for energy. As for fat, it regenerates a small amount of glucose—but not enough to feed the brain and nerve tissues.
type 2 diabetes
the body cells fail to respond to insulin by taking up blood glucose. This condition tends to occur as a consequence of obesity, and the best preventive measure is often to maintain a healthy body weight. Predominant type of diabetes •Lose sensitivity to insulin• Obesity underlies many cases• Other factors •Middle age and physical inactivity •Body fat accumulation •Genetic inheritance prevention: Maintain healthy body weight •Nutritious eating pattern •Moderate in calories •Low in saturated fat •High in vegetables, legumes, fruit, fish, poultry, and whole grains •Regular physical activity
Polysaccharides
the glucose in food occurs in long strands of thousands of glucose units. Starch, glycogen and most of the fibers.
fibers
the indigestible parts of plant foods, largely nonstarch polysaccharides that are not digested by human digestive enzymes, although some are digested by resident bacteria of the colon. Fibers include cellulose, hemicelluloses, pectins, gums, mucilages, and a few non-polysaccharides such as lignin. -Fibers lend structure to plants and perform other functions. -Human digestive enzymes cannot break the chemical bonds of fibers. -Some fiber is susceptible to fermentation by bacteria in the colon. -Animal storage form of glucose
Green plants make carbohydrate
through photosynthesis in the presence of chlorophyll and sunlight. In this process, water absorbed by the plant's roots donates hydrogen and oxygen. Carbon dioxide gas absorbed into its leaves donates carbon and oxygen. Water and carbon dioxide combine to yield the most common of the sugars, the single sugar glucose.
soluble fibers
water soluble and form viscous gels •fermented by intestinal bacteria •Found in oats, barley, legumes, and citrus fruits .•May help lower blood cholesterol and control blood glucose levels. •"bulk" •Softens stool and makes it easier to pass •Removes excess fat from intestines •Oats, fruit fibers, nuts -promote the health of the colon. Many kinds are readily fermented by colonic bacteria, and products of their fermentation: nourish cells of the colon and promote resistance to colon cancer, reduce inflammation, and support immunity.
Indigestible carbohydrates.
which include most of the fibers in foods, yield little or no energy but provide other important benefits
Can glucose be converted to fat?
yes, But fat cannot be converted to glucose •Protein converted to glucose when insufficient carbohydrate •Protein-sparing action of carbohydrate
The Glycemic Index of Food
•A ranking of foods according to their potential for raising blood glucose relative to a reference dose of glucose •Measures the degree of elevation of blood glucose and insulin •Food score•A steady diet of high-glycemic ultra-processed foods may be linked with chronic diseases •Metabolism affects the body's insulin response: •Diabetes•Type 1 diabetes: The pancreas fails to produce insulin •Type 2 diabetes: Body cells fail to respond to insulin
The Body's Use of Glucose
•Glucose is the basic carbohydrate that each cell of the body uses for energy •Body must have glucose available for its cells at a steady rate all day •Body cannot use polysaccharides or disaccharides or even fructose or galactose
Which foods contain starch?
•Grains: wheat, corn, rice, rye, barley, oats •Root and tuber vegetables: beets, carrots, potatoes, sweet potatoes •Dried beans, peas, and lentils: navy beans, split peas
High-Fructose Corn Syrup (H C F S)
•Is H C F S more harmful than sucrose?•Research indicates virtually identical metabolic effects•All common added sugars are similar•Shouldn't be consumed in excess
Why Do Nutrition Experts Recommend Fiber-Rich Foods?
•People who regularly eat fiber-rich fruit, legumes, vegetables, nuts, seeds, and whole grains are often reported to be healthier than those who do not •There are two types of fibers: •Soluble fibers:•Readily dissolve in water•Many kinds are readily fermented •Insoluble fibers: •Not viscous•Retain shape and texture
Hints of Metabolic Mayhem
•Some important metabolic links exist among added sugars, obesity, and chronic diseases •Insulin•Insulin resistance: Body cells fail to respond to insulin's effects •Fructose•Handled differently in the body•Affects appetite differently •Body fatness and blood lipids•Stimulates the liver to synthesize new fat molecules that can be stored in adipose tissue and this can cause damaging non-alcoholic fatty liver disease(N A F L D)