Bad Advice: "Avoid fats"
Fat actually satisfies the
appetite longer and fats are essential for good health (Gerber 2000)
Question: I've been
trying to determine the effects of excess sugar in my diet.
According to the body building publications I read, I should avoid
sugar because it easily converts to fat in the bloodstream. Further,
I've read I should stay away from fruit. True, it is high in
vitamins and minerals, but it contains the simple sugar fructose
which ends up as fat in the bloodstream. Is this true? And, if in fact sugar
is converted to fat, what does that say about the so called
"Fat Free" products on the market? Have they simply hidden
the fat as various types of sugar in the label's carbohydrate
category? I've been developing
a diet containing moderate protein, low fat (about 10-15%), and the
rest carbohydrates. Combining this with exercise, I've steadily lost weight
and am never hungry though I'm typically a big eater. If, in
fact, sugar has a negative effect on weight loss, should I reduce my
sugar intake as much as possible?
Answer: First, sugar
in the diet is a broad term. This is because food that falls into
the macronutrient group of carbohydrate is all composed of varying
types of sugars. This includes bread, pastas, rice, fruit and many
combination foods like candy bars that have carbohydrate, protein
Sugar by itself is
not inherently bad. Rather it is the body's response to sugar that
can be problematic for some people. Remember that in order to
produce energy the body must first convert food to sugar for
oxidation (burning). So, regardless of whether you've eaten
proteins, carbs or fats it will ultimately end up as sugar (except
in a very particular instance).
This is good because
your brain will only use sugar for energy. In fact it is the sugar
or glucose level of the brain that determines feelings of hunger,
satiation or any specific craving for a certain food.
The reason why sugar
has such a bad rap has to do with insulin. In the body, insulin has
a very important job. It is secreted in response to elevated blood
sugar levels, such as those that occur after a meal, and it pushes
that sugar into storage. First to be filled are the tissues of the
muscles and the liver where the sugar (which is what your meal has
become) is converted to glycogen. Glycogen is the body's fuel of
choice for high intensity aerobic activity because it is readily
available and because it is quickly converted to ATP for energy.
The problem is that
the body only has storage for about 2500 calories worth of glycogen
providing your stores were totally empty (which is impossible). Most
people only have room to store about 500 calories of glycogen from
any given meal. After these storage areas become full, insulin
pushes the remaining sugar into the other infinite storage area, FAT
The critical thing is
not whether a food has sugar, but how quickly the sugar enters the
blood stream. Food is actually categorized by this rate of entry.
This is known as the glycemic index. On this scale sucrose (table
sugar) is given a 100 rating. Foods like honey, cooked carrots,
sweet potatoes and other starchy vegetables and fruits including
bananas are even higher. Broccoli is rated 34 on the glycemic index.
Things like pastas and breads are somewhere in the middle. Fructose
or fruit sugar is rated a 20 on the glycemic index (GI). It is one
of the lowest GI sugars known.
To reduce the impact
of dietary carbohydrate you should strive to eat foods low on the
glycemic scale. You can also reduce the GI of foods or meals by
eating a combination of protein carbohydrates and fat each time you put food
into your body. Monounsaturated fat (like avocados, almonds and
olive oil) are especially good because they do not affect insulin or
other hormones and they very effectively lower the GI of other foods
by slowing absorption. Adding small amounts of fat to each meal also
results in the release of certain hormones from your stomach that
will help you feel satisfied and reduce the number of meals you need
which will assist you in reaching your ideal weight.
So, in summary, fruit
isn't bad depending upon which fruit you choose; eating protein,
fruit and carbohydrates together helps more; and large amounts of any
carbohydrate will increase blood sugar levels rapidly which can
result in excess fat storage.
One note: how
your body reacts to carbohydrate is a genetically predetermined
thing. If you have a history of diabetes, heart disease or
hypertension in your family you are likely to have these problems
yourself. The best way to avoid this trap is to consistently eat low
GI meals and snacks.
Regarding reduced fat
and fat free foods, you are absolutely right. The fat in these foods
has been replaced by simple carbohydrates which raise their GI. This fat
free trend has been the largest unsuccessful dietary experiment ever
conducted. The result: over the last decade the average American is
33% fatter! This despite the proliferation of these low and nonfat
source of nutrients and supplements.
did we qualify them ?