The Low Fructose Diet
by Cassandra Forsythe, PhD(c), CSCS, CISSN


Are you looking for that nutritional edge to get your body
composition to the next level?
Have you been eating your "five-a-day" like a good
girl should, but just can't shake that last bit of icing off
your former muffin-top?

Well, take close note: if you reduce the fructose in your diet,
you will lose that stubborn body fat!


Fructose Metabolism 101, the Simplified Version
Fructose is a type of simple sugar (a carbohydrate in its
simplest form) that is much different than its sister sugar, namely
glucose. When you eat fructose, it's absorbed more
slowly in the intestine, and its absorption is slightly
limited.
Some people—like those with diabetes, see fructose as a
superior simple sugar because it doesn't get used as quickly
or as efficiently. What they don't realize, is that fructose is
normally consumed at the same time as glucose, which speeds
up the absorptive process.
Once fructose passes through the intestine, it's quickly
taken to the liver for processing. Here, it has two fates:
it's either turned into glucose and then stored as liver
glycogen; or it's used for energy by liver cells.
Unlike glucose, fructose can only be metabolized in the
liver, whereas glucose can be passed to other body tissues, like
your muscles.


Why Fructose is a Problem for Dieters:
If you have a lot of fructose in your diet, it only has one
place to go: your liver. If your liver glycogen levels are full,
which is the case all times of the day except before you eat
breakfast, then that fructose is turned into fat!
Since your liver doesn't want to store this new fat, it
ships it to other parts of your body; places you don't
want it, like your belly and butt.
Do you now see why too much fructose in your diet can be one of
the biggest reasons you can't shrink those last few fat
cells?



How Do I Avoid Eating Fructose?
When people hear the word fructose, they usually think fruit.
Ready for a shocker? Fruit is actually not the major source
of fructose in your diet!
Yes, it does have fructose, but only certain fruits are high in
it, while others are relatively low. Not all fruits are bad for
your body composition; vegetables are the same way.

The major contributors of fructose in your diet, in
descending order, are as follows:

• High Fructose Corn Syrup (HFCS)
• Table Sugar, which is a 50:50 combination of glucose and
fructose
• Brown Sugar
• Maple Sugar
• Cane Sugar
• Molasses
• Honey
• Concentrated Fruit Juice
• Fruits
• Vegetables
Avoid the top eight in this list at all costs!

Read labels carefully, because HFCS is hiding in almost every
food you eat nowadays. And, just because honey is natural,
doesn't mean you should use it in abundance.


How Do We Really Know Fructose Makes You Fat?
You must have been living under a rock if you haven't
already heard about HFCS being related to every common human
disease we face today, such as diabetes, heart disease, obesity and
cancer.
This relationship was first discovered in lab experiments with
rodents. (1) When a high fructose diet (about 50-60% of total
energy intake) is given to rats, they present symptoms of the
Metabolic Syndrome, which is the precursor to full-blown diabetes
and heart disease.
These animals develop high blood pressure, endothelial
dysfunction, weight gain, increased abdominal fat,
hyper-triglyceridemia and insulin resistance. The weight and fat
gain is thought to be due to leptin resistance; rats that eat a
high fructose diet long-term have higher leptin levels than rats
that don't eat a lot of this simple sugar.




Researchers then concluded that in humans, it's the
fructose and not glucose that begins the cascade of Metabolic
Syndrome risk markers (2); and this seems to be initiated by
insulin resistance. Men forced to eat experimental high fructose
diets develop insulin resistance within a week (3), compared to no
insulin abnormalities in people given a high starch diet.
Sucrose, also known as "table sugar" (glucose and fructose
combination), is even worse: people given a 28% sucrose diet for 10
weeks not only develop insulin resistance, but also gain weight and
have increased blood pressure!
In another study, when overweight women were put on a
"no-restriction" diet high in either sucrose, fat, or starch, only
the high starch diet group lost weight and body fat. (4)
Today, most Americans are eating about 70-100 grams of fructose
per day, and we're getting fatter by the minute. In bright contrast
to today's world, this nation consumed just 15 to 40 grams of fruit
& veggie-derived fructose in the 19^th century, when
we weren't even close to being this chubby. (5)


Why Does Fructose Cause Fat-Gain?
Fructose and fructose-containing foods will usually make your
meals taste better, so you end up eating much more than necessary.
They also fail to make you feel satisfied after you eat them, due
to inadequate stimulation of leptin and ghrelin, the two satiety
hormones. (6)
There is also evidence that fructose slows your metabolism: kids
who drink sodas and fruit juices (both are rich in HFCS and
fructose) are fatter than those who don't drink them, but who
eat the same amount of calories. (7)


So, What Kinds of Fruits and Vegetables Can I Eat and Not Get
Fat?
Although fruit does contain some fructose, it's not the
only sugar that it contains. Fruit is beneficial for you because
it's the best natural source of antioxidants that help you
fight free-radicals, a major cause of aging and muscle damage. It's
also an important source of fiber.
Your best bet is to choose fruits that are low in fructose, and
only eat the higher fructose fruits in the morning, when your liver
glycogen levels are low. At this time, your liver can use or store
the fructose without converting it to fat.

The following fruits are highest in fructose (per typical
serving size)*. They contain more than 4 grams of fructose per
serving.

Stay away from these outside of an occasional breakfast:

• apple
• banana
• cherries (1 Cup)
• grapes (1 Cup)
• mango
• melon (2 wedges)
• orange
• pear
• pineapple (2 rings)
• watermelon (1 large slice)
These fruits are lowest in fructose; they contain less than 4
grams of fructose per serving.

You can eat these with less restriction:


• apricot
• avocado (1/3 medium; yes, it's a fruit)
• blackberries (1/2 cup)
• figs
• grapefruit (1/2 medium)
• papaya
• peach
• plum
• raspberries (1/2 cup)
• strawberries (1/2 cup)
• tomato (yes, also a fruit)
*Note, these values were calculated by adding all of the
fructose plus have of the sucrose per typical serving size (i.e., a
typical apple weighs 120 grams)
Vegetables are much lower in fructose than fruits. The highest
fructose-containing vegetable are corn and sweet potatoes, and they
only have roughly 1.2 grams of fructose per serving. If you're
really trying to keep this sugar low, also avoid white potatoes and
green peas.


Bottom Line:
Fructose may be one of the reasons your body is not dropping the
stubborn body fat you've been fighting for weeks, or even
months. Before you start avoiding the produce section of the
grocery store, start scanning the labels of some of your most
frequently consumed foods.
Does your salad dressing contain HFCS? Do you douse your morning
eggs with HFCS-laden ketchup? Or maybe you're known to eat
"all-natural" products made with honey?
Once you've eliminated these major fructose-suspects, turn
to your fruit intake. Don't eliminate it completely because
some fruit will aid your overall health and beauty by fighting
free-radical-induced aging and muscle damage. Just choose fruits
lower in fructose.
Apples may keep the doctor away, but with their high fructose
content, they'll keep your sexiest bikini just as out of sight.


About the Author:

Cassandra Forsythe is a Ph.D. candidate at the University of
Connecticut studying exercise science and nutrition. She received
her M.S. in Human Nutrition and Metabolism and her B.S. in
Nutrition and Food Science from the University of Alberta in
Edmonton, Canada. She is certified as a Strength and
Conditioning Specialist (CSCS) from the National Strength and
Conditioning Association (NSCA), and is a Certified Sports
Nutritionist (CISSN) through the International Society of Sports
Nutrition (ISSN).


At UConn, Cassandra studies under Jeff Volek, PhD, RD
researching the effects of low-carbohydrate ketogenic diets and
resistance exercise on risk factors for heart disease, diabetes and
body composition. She works as a nutritional educator and
weight-loss coach and is the author of two popular books for women:
"The New Rules of Lifting for Women", co-authored with
Lou Schuler and Alwyn Cosgrove, and "Women's Health
Perfect Body Diet". In August 2008, she will begin her
dietetic internship to become a Registered Dietitian and will
complete her PhD in January 2009. She can be reached at her website.


References

1. Segal MS, Gollub E, Johnson RJ (2007) Is the fructose index
more relevant with regards to cardiovascular disease than the
glycemic index? Eur J Nutr 46:406-417

2. Elliott SS, Keim NL, Stern JS, Teff K, Havel PJ (2002)
Fructose, weight gain, and the insulin resistance syndrome. Am J
Clin Nutr 76:911–922

3. Beck-Nielsen H, Pedersen O, Lindskov HO (1980) Impaired
cellular insulin binding and insulin sensitivity induced by
high-fructose feeding in normal subjects. Am J Clin Nutr
33:273–278

4. Raben A, Vasilaras TH, Moller AC, Astrup A (2002) Sucrose
compared with artificial sweeteners: different effects on ad
libitum food intake and body weight after 10 wk of supplementation
in overweight subjects. Am J Clin Nutr 76:721–729

5. Raben A, Macdonald I, Astrup A (1997) Replacement of dietary
fat by sucrose or starch: effects on 14 d ad libitum energy intake,
energy expenditure and body weight in formerly obese and
never-obese subjects. Int J Obes Relat Metab Disord
21:846–859

6. Teff KL, Elliott SS, Tschop M, Kieffer TJ, Rader D, Heiman M,
Townsend RR, Keim NL, D'Alessio D, Havel PJ (2004) Dietary
fructose reduces circulating insulin and leptin, attenuates
postprandial suppression of ghrelin, and increases triglycerides in
women. J Clin Endocrinol Metab 89:2963–2972

7. Dennison BA, Rockwell HL, Baker SL (1997) Excess fruit juice
consumption by preschool-aged children is associated with short
stature and obesity. Pediatrics 99:15–22



© 1998 — 2008 Testosterone,
LLC. All Rights Reserved.