All About Carbohydrates

by Ryan
Andrews
, February 2nd, 2009.

What are carbohydrates?

Carbohydrates are organic molecules typically classified according to their
structure. And, structurally speaking, there are two types of carbohydrates:
simple and complex.
Simple carbohydrates are smaller, more easily processed molecules known as
mono- and disaccharides since they contain either one sugar molecule or two
sugar molecules linked together.
Complex carbohydrates, on the other hand, are called polysaccharides since
they have more than two sugar groups linked together.
Monosaccharides are the simplest form of carbohydrate and cannot be broken
down any further since they contain only a single sugar group. Oligosaccharides
consist of short chains (di-, tri-, etc) of monosaccharide units all put
together. And polysaccharides are long chains of monosaccharide units all put
together.

Monosaccharides

Glucose
Fructose
Galactose
Mannose
Ribose

Oligosaccharides

Sucrose
Maltose
Lactose
Trehalose

Polysaccharides

Digestible
Starch and
dextrins
Glycogen
Partially
digestible

Inulin
Raffinose
Indigestible
Cellulose
Pectin
Here are a couple of diagrams that show what some of these structures look
like:
Each subtype of carbohydrate has different effects in the human body
depending on its structure and its food source, which affect things like:
  • How quickly and/or easily the carbohydrate molecule is digested and absorbed
  • Which other nutrients are provided along with the carbohydrate source; for
    example, fat and protein slow down the digestion and/or absorption
  • Our perceptions of the carbohydrates’ texture and sweetness
  • Enzyme action in the mouth and gut

Why is carbohydrate intake so important?

Carbohydrate consumption can alter energy dynamics and disease progression in
the body.
All carbohydrates we consume are digested into monosaccharides or
simple sugars before they’re absorbed by the body, regardless of whether the
food source is a simple sugar cube or a high-fibre, low glycemic index bowl of
oatmeal. It’s just that the “healthier carbs” are digested and absorbed much
slower while the “non-healthy” carbs are digested very quickly.
Once broken down and absorbed, these monosaccharides/sugars go to the liver
to fill energy stores. After that, they enter the bloodstream and venture out to
the other cells of the body. This is when insulin is released to handle this
“sugar load” on the body.
See here for simple animation.
Carbohydrates are primarily a source of immediate energy for all of your
body’s cells.
As previously mentioned, carbohydrates also cause a release of insulin. A
larger insulin response can be beneficial at certain times (like after an
intense workout) and not so beneficial at certain times (like before bed).

What you should know

Although the fundamental process of digestion is the same, people differ in
their tolerance and handling of carbohydrates. However, carbohydrate type also
plays an important role.
When the diet consists of simple sugars and refined
carbohydrates (which the body breaks down rapidly), one may notice elevations in
blood triglyceride levels, bad cholesterol, and insulin resistance.
On the other hand, carbohydrates that are digested and absorbed slowly, such
as whole grains, fruits, and vegetables, can help to control insulin response,
energy levels, and body composition. Such unrefined, unprocessed, complex
carbohydrate sources may reduce triglycerides and improve one’s cholesterol
profile (Jenkins et al 1987). Other benefits of a lower glycemic diet include
increased vitamin and mineral intake, increased fibre intake, enhanced satiety,
a higher thermic effect of feeding, and blood sugar control (Ludwig & Eckel
2002; Ludwig 2000).
The chart to the right compares the glycemic response (i.e., the rise in
blood glucose levels) between eating a high-GI food (glucose) and a low-GI food
(beans). Notice how with glucose (red area), blood glucose rises quickly and
peaks shortly after ingestion.
The minimal recommended intake for carbohydrate is 130 grams per day for the
general population. The amount of carbohydrate that should be consumed depends
on body size and activity levels: bigger and/or more active people need more
while smaller and more sedentary people require less. Intake is also dependent
on dietary fat and protein intake.
The minimal recommended intake for fibre is 25 grams per day. The optimal
amount is around 35 grams/day for women and 48 grams/day for men. Fibre comes in
different forms (soluble/insoluble) and is important for satiety, blood fat
levels, colon cancer, motility and gut health (Brown et al 1999; Wu et al 2003;
Berkow & Barnard 2006; Wylie-Rosett et al 2004; Martinez et al 1997;
Martinez et al 1996; Peters et al 2003; McKeown-Eyssen et al 1994; Macrae 1999;
Park et al 2005; Tse et al 2000; Howard et al 2000; Griffenberg et al 1997).
Fibre is found in vegetables, legumes, fruits, nuts, seeds, and whole
grains.

For extra credit

While carbohydrate intake is a chief determinant of blood sugar levels,
research suggests that consuming three whole grain foods per day decreases one’s
risk of developing type II diabetes by about 30% (Venn & Mann 2004).
Dextrose seems to be faster than fructose for post-exercise muscle glycogen
re-synthesis (Blom 1987; Van Den Bergh et al 1996).
Here’s additional reading on this topic: Lean Eating Part II

Summary and recommendations

The average person’s minimum carbohydrate intake should be 130 grams per day,
with a majority coming from vegetables and fruits. Higher amounts of
carbohydrates are needed with increased muscle mass and increased physical
activity levels. However, excessive carbohydrate consumption will be stored for
future use (as fat or glycogen).
The rate at which the carbohydrate is digested and absorbed can influence
body composition and health.
  • A slower carbohydrate breakdown from lower glycemic carbohydrates is better
    for satiety, blood sugar, and body composition. These carbohydrates are found in
    vegetables, fruits, legumes, and whole grains.
  • Rapid digestion of simpler, higher-glycemic carbohydrates is beneficial
    during the pre- and post-workout periods.
Consume at least 25 grams of fibre per day from vegetables, fruits, legumes,
nuts, seeds, and whole grains to ensure optimal health and body composition.

References

Jenkins DJ, Wolever TM, Kalmusky J, Guidici S, Giordano C, Patten R, Wong GS,
Bird JN, Hall M, Buckley G. Low-glycemic diet in hyperlipidemia: use of
traditional starchy foods. Am J Clin Nutr 1987;46:66-71.
Venn BJ, Mann JI. Cereal grains, legumes, and diabetes. Eur J Clin Nutr
2004;58:1443-1461.
Ludwig DS & Eckel RH. The glycemic index at 20y. Am J Clin Nutr
2002;76:264S-265S.
Ludwig DS. Dietary glycemic index and obesity. J Nutr 2000;130:280S-283S.
Blom PC, hostmark AT, Vaage O, Kardel KR, Maehlum S. Effect of different
post-exercise sugar diets on the rate of muscle glycogen synthesis. Med Sci
Sports Exerc 1987;19:491-496.
Van Den Bergh AJ, Houtman S, Heerschap A, Rehrer NJ, Van Den Boogert HJ,
Oeseburg B, Hopman MT. Muscle glycogen recovery after exercise during glucose
and fructose intake monitored by 13C-NMR. J Appl Physiol 1996;81:1495-1500.
Brown L, Rosner B, Willett WW, Sacks FM. Cholesterol-lowering effects of
dietary fiber: a meta-analysis. Am J Clin Nutr 1999;69:30-42.
Wu H, Dwyer KM, Fan Z, Shircore A, Fan J, Dwyer JH. Dietary fiber and
progression of atherosclerosis: the Los Angeles Atherosclerosis Study. Am J Clin
Nutr 2003;78:1085-1091.
Berkow SE & Barnard N. Vegetarian diets and weight status. Nutr Rev
2006;64:175-188.
Wylie-Rosett J, Segal-Isaacson CJ, Segal-Isaacson A. Carbohydrates and
increases in obesity: does the type of carbohydrate make a difference? Obes Res
2004;12 Suppl 2:124S-129S.
Martinez ME, McPherson RS, Levin B, Glober GA. A case-control study of
dietary intake and other lifestyle risk factors for hyperplastic polyps.
Gastroenterology 1997;113:423-429.
Martinez ME, McPherson RS, Annegers JF, Levin B. Association of diet and
colorectal adenomatous polyps: dietary fiber, calcium, and total fat.
Epidemiology 1996;7:264-268.
Peters U, Sinha R, Chatterjee N, et al. Dietary fibre and colorectal adenoma
in a colorectal cancer early detection programme. Lancet 2003;361:1491-1495.
McKeown-Eyssen GE, Bright-See E, Bruce WR, et al. A randomized trial of a low
fat high fibre diet in the recurrence of colorectal polyps. Toronto Polyp
Prevention Group. J Clin Epidemiol 1994;47:525-536.
Macrae F. Wheat bran fiber and development of adenomatous polyps: evidence
from randomized, controlled clinical trials. Am J Med 1999;106:38S-42S.
Park Y, Hunter DJ, Spiegelman D, et al. Dietary fiber intake and risk of
colorectal cancer: a pooled analysis of prospective cohort studies. JAMA
2005;294:2849-2857.
Tse PW, Leung SS, Chan T, Sien A, Chan AK. Dietary fibre intake and
constipation in children with severe developmental disabilities. J Paediatr
Child Health 2000;36:236-239.
Howard LV, West D, Ossip-Klein DJ. Chronic constipation management for
institutionalized older adults. Geriatr Nurs 2000;21:78-82.
Griffenberg L, Morris M, Atkinson N, Levenback C. The effect of dietary fiber
on bowel function following radical hysterectomy: a randomized trial. Gynecol
Oncol 1997;66:417-424.
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About dkpilates

Pilates Instructor, Yoga Instructor, Personnel trainer and Group Fitness Instructor. Don teaches Contemporary and the Authentic forms of Pilates, in the later 90's, Don began his study of Yoga. His study of Yoga includes the Hatha, Iyengar, Bikram, and Astanga disciplines. His other areas of interest in fitness include Martial Arts, Spin, Boot Camp Training, and Weight Training. Don has extensive training and certifications from AFFA, IDEA, MadDog, B-Fit and Polestar. Don Continues his of Pilates education with Michelle Larson in Santa Fe New Mexico. His personal philosophy related to fitness is to aid students in a personalized balance of strength, stamina and flexibility. He is dedicated to design a program specifically for his students independent of the season of their life to create functional movement and help them reach their fitness goals.
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One Response to All About Carbohydrates

  1. Pingback: All About Recovery | The Core Matrix

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