Transcript Carbohydrates

Carbohydrates
Carbohydrates
• Carbohydrates make up the largest
volume of our daily food.
• 60 % of our food should be from
carbohydrates.
Carbohydrates are Macronutrients
• Macronutrients are nutrients that provide
calories or energy. Nutrients are substances
needed for growth, metabolism, and for other
body functions. Since “macro” means large,
macronutrients are nutrients needed in large
amounts. There are three macronutrients: carbs,
protein, and fat.
Simple vs. Complex Carbs
• Carbohydrates are classified as simple or
complex. The classification depends on:
– the chemical structure of the food
– how quickly the sugar is digested and
absorbed.
Simple vs. Complex Carbs
* Simple carbohydrates have one (single) or two
(double) sugars.
* Complex carbohydrates have three or more
sugars.
Glucose
• Glucose is the major kind of simple sugar. It is the
basic source of energy for all living things.
• We are not able to make our own glucose, so we
eat plants for their storage of glucose. We then
burn glucose for energy.
• If you do not use the glucose, it gets turned into
glycogen which is stored energy in the muscles
and liver.
Single Sugar Carbs
• Examples of single sugars from foods include:
– Fructose (found in fruits)
– Galactose (found in milk products)
Fructose
• Fructose: known as fruit sugar. Most plants
contain this sugar, especially fruits and saps.
• Fructose is a monosaccharide, a simple
natural sweetener. It is the sweetest of the
naturally occurring nutritive (caloric)
sweeteners and has many unique functional
and nutritional properties that make it a
valuable food ingredient.
Fructose
• Fructose occurs naturally in fruits, vegetables
and their juices, as well as honey. It gives
these foods their sweet taste. Fructose in
crystalline form has been widely used for the
past 20 years as a nutritive sweetener in foods
and beverages.
Galactose
• Galactose is in the same family as sucrose,
fructose and lactose.
• Galactose is found in milk and whey, as well as
the human body.
Double Sugar Carbs
• Double sugars include:
– Lactose (found in dairy)
– Maltose (found in certain vegetables and in
beer)
– Sucrose (table sugar)
Lactose
• Carbohydrates come mainly from plant
sources, although milk and milk products
contain some carbohydrates in the form of
lactose.
• Lactose: known as milk sugar, is found as the
principal carbohydrate in milk.
Maltose
• Maltose: known as malt sugar, is found in
grains.
Sucrose
• Sucrose: commonly known as table sugar, beet or
cane.
• Sugar or more specifically sucrose is a
carbohydrate that occurs naturally in every fruit
and vegetable. It is the major product of
photosynthesis, the process by which plants
transform the sun's energy into food. Sugar
occurs in greatest quantities in sugar cane and
sugar beets from which it is separated for
commercial use.
Simple Carbs
• Simple carbohydrates that contain vitamins
and minerals occur naturally in:
– Fruits
– Milk
– milk products
– Vegetables
Simple Carbs in refined foods
• Simple carbohydrates are also found in
processed and refined sugars such as:
– Candy
– Regular (nondiet) carbonated beverages,
such as soda
– Syrups
– Table sugar
Refined sugars explained
• Refined sugars provide calories, but lack
vitamins, minerals, and fiber. Such simple sugars
are often called "empty calories" and can lead to
weight gain. Also, many refined foods, such as
white flour, sugar, and white rice, lack B vitamins
and other important nutrients unless they are
marked "enriched." It is healthiest to get
carbohydrates, vitamins, and other nutrients in
as natural a form as possible -- for example, from
fruit instead of table sugar.
Complex Carbs
• Complex carbohydrates:
– Are often referred to as "starchy" foods
– include:
• Legumes
• Starchy vegetables
• Whole-grain breads and cereals
Starch = Complex Carbs
• Starch in the body breaks down simple sugars.
The body has to break down all sugar and
starch into glucose to use it.
• All starchy foods are plant foods, seeds are the
richest source; 70% of their weight is starch.
Fiber
Dietary fiber, also known as roughage or bulk,
includes all parts of plant foods that your body can't
digest or absorb. Unlike other food components
such as fats, proteins or carbohydrates — which
your body breaks down and absorbs — fiber isn't
digested by your body. Therefore, it passes
relatively intact through your stomach, small
intestine, colon and out of your body. It might seem
like fiber doesn't do much, but it has several
important roles in maintaining health.
Fiber
• Dietary fiber — found mainly in fruits,
vegetables, whole grains and legumes — is
probably best known for its ability to prevent or
relieve constipation. But fiber can provide other
health benefits as well, such as lowering your risk
of diabetes and heart disease.
• Fiber is commonly classified into two categories:
those that don't dissolve in water (insoluble
fiber) and those that do (soluble fiber).
Insoluble Fiber
• This type of fiber promotes the movement of
material through your digestive system and
increases stool bulk, so it can be of benefit to
those who struggle with constipation or
irregular stools. Whole-wheat flour, wheat
bran, nuts and many vegetables are good
sources of insoluble fiber.
Soluble Fiber
• This type of fiber dissolves in water to form a
gel-like material. It can help lower blood
cholesterol and glucose levels. Soluble fiber is
found in oats, peas, beans, apples, citrus
fruits, carrots, barley and psyllium. (a type of
plant- the seeds and husks are ground and
used in foods)
Benefits of a high fiber diet
• Normalizes bowel movements.
• Helps maintain bowel integrity and health.
• Lowers blood cholesterol levels
• Helps control blood sugar levels.
• Aids in weight loss.
Sources of Fiber
Good choices include:
•
•
•
•
•
Grains and whole-grain products
Fruits
Vegetables
Beans, peas and other legumes
Nuts and seeds
Poor Sources of Fiber
• Refined or processed foods — such as canned
fruits and vegetables and pulp-free juice,
white bread and pasta, and non-whole-grain
cereals — are lower in fiber content. The
grain-refining process removes the outer coat
(bran) from the grain, which lowers its fiber
content. Similarly, removing the skin from
fruits and vegetables decreases their fiber
content.
Why do we need carbs?
• Carbohydrates are the main source of fuel for
the body.
• Carbohydrates are easily used for energy.
• Every tissue and cell in the body can use
glucose for energy.
Why do we need carbs?
• Carbohydrates are the most efficient source of
fuel for your muscles.
• An ample supply of carbohydrates is absolutely
necessary to sustain a healthy existence and a
must if your goal is to reduce your body fat and
enhance your fitness level.
Why do we need carbs?
• Carbohydrates are the element of our food that
supplies energy.
• Carbohydrates also play a vital part of the
digestive process, and of the metabolism and
oxidation of protein and fat.
What about low or no carb diets?
• These diets help you lose weight, BUT they are
not healthy. The weight you lose will only be
short term.
• Without carbohydrates, your body begins to burn
glycogen reserves, so you lose that energy along
with water weight.
• Glucose from carbohydrates provides energy for
the nerve and brain cells. Don’t cut them out!
The Real Problem with Carbs
• The issue with carbohydrates is that we eat too
many of the bad types of carbohydrates.
• Nearly two-thirds of our potatoes are processed
into french fries and chips!
• Many of our juices have added sugar!
• Many people eat too many refined sugars such as
candy and cakes.
Keeping carbs healthy
• To increase complex carbohydrates and healthy
nutrients:
– Eat more fruits and vegetables.
– Eat more whole-grain rice, breads, and cereals.
– Eat more legumes (beans, lentils, and dried
peas).
**Read your food labels**
Recommended servings
• Here are recommended serving sizes for foods
high in carbohydrates:
• Vegetables: 1 cup of raw vegetables, or 1/2 cup
cooked vegetables, or 3/4 cup of vegetable juice
• Fruits: 1 medium-size fruit (such as 1 medium
apple or 1 medium orange), 1/2 cup of a canned
or chopped fruit, or 3/4 cup of fruit juice
Recommended servings
• Here are recommended serving sizes for foods
high in carbohydrates:
• Breads and cereals: 1 slice of bread; 1 ounce or
2/3 cup of ready-to-eat cereal; 1/2 cup of cooked
rice, pasta, or cereal
• 1/2 cup of cooked dry beans, lentils, or dried
peas
• Dairy: 1 cup of skim or low-fat milk
Sources for this presentation
• http://www.mckinley.illinois.edu/handouts/macr
onutrients.htm
• http://www.nlm.nih.gov/medlineplus/ency/articl
e/002469.htm
• http://www.fructose.org/facts.html
Sources for this presentation
• http://www.galactose.org
• http://www.elmhurst.edu/~chm/vchembook/54
6sucrose.html
• http://www.mayoclinic.com/health/fiber/NU000
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