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FATS AND THE INSULIN INDEX
When you consume fats, they are one of the macronutrients that do not stimulate
a glucose response and so do not, in themselves raise insulin levels. The insulin
Index is a study of how food types actually stimulate insulin production. We
know that carbohydrates and proteins stimulate insulin production. We know that
it is best to consume lower GI foods and if you really do have to combine carbohydrates,
you should eat them free from fat, or as low in fat as possible. Fats are best
consumed alone or only with low insulin response proteins.
Forms of Fats
In this section, we'd like to demonstrate that not all fats were created equal.
Specifically, we'll briefly discuss:
1. Fat Structure - Fatty Acid Chains and TGs
2. MCTs - Medium Chain Triglycerides
3. Olive Oil - Monounsaturated Fatty Acids
4. CLA - Polyunsaturated Fatty Acids
5. Fish Oil - Omega 3 Polyunsaturated Fatty Acids
As discussed, there are three different types of fatty acids; saturated (coming
from animal fats), monounsaturated (coming from olive oil and avocados), and
polyunsaturated (coming from flax oil, hemp oil, fish oil, canola oil, safflower
oil, etc). Dietary fat, rather than simply floating around as free fatty acids,
typically is packaged up in the form of a triglyceride. Basically, a triglyceride
consists of 3 fatty acids (usually all of the same type) bound together by a
glycerol backbone. Essentially, the glycerol backbone has 3 carbons and a fatty
acid is attached (via a dehydration/synthesis reaction) to each of the 3 carbons.
Based on this structural phenomenon, scientists have recently begun exploring
an interesting development in fat science. They've begun making "structured
lipids." In essence what they're doing is making diacylglyerols (2 of the
carbons have fatty acids attached while 1 does not) and special triacylglycerols
(where there are fats of different lengths and properties attached to each carbon).
In clinical studies, these structured lipids have been shown to increase protein
synthesis in patients suffering from wasting. In addition, these fats are easily
oxidized (like the long chain fatty acids in fish oil) which leads to a thermogenic
response rather than a storage response. As a result these structured lipids
are now being heavily studied. While they're not on shelves yet, we wouldn't
be surprised if these structured lipids become food additives in the near future.
MCT's and CLA, probably due to their early introduction to the weightlifting
scene and the huge media hype associated with this introduction, have gotten
a bad reputation. These fats may, in fact, assist in weight loss.
MCT's, due to their medium chain length, are easily oxidized by skeletal muscle.
This is due to the fact that MCT's are quickly and easily transported to the
fat furnace, the mitochondrion. As a result, research (Hill et al 1989) has
demonstrated that TEF (thermogenic effect) with MCTs is double that of other
fats, making it comparable to protein in this regard.
CLA has remained a relative mystery to the research community. This is probably
due to the various forms (isomers) of CLA. Regardless, some research (Blankson
et al 2000) has shown that 12 weeks of CLA supplementation (at doses above 3.4g/day)
can increase LBM and decrease fat mass vs. olive oil. While the olive oil group
gained 1.5 lbs of fat and no lean body mass, the CLA group lost 4.5 lbs of fat
and gained 3 lbs of LBM.
Speaking of olive oil, even this "good fat" is better than saturated
fat for body composition. In a study comparing safflower oil, beef fat, palm
fat, and olive oil, it was shown that olive oil leads to a 14% higher oxygen
consumption rate than the other fats.
Finally, most research has shown that the favorite fats for humans are those
in fish oil. Delarue et al (1996) showed that fish oil supplementation (6g/day
added to the diet) dramatically changed the metabolism of fats and carbohydrates.
During an OGTT (oral glucose tolerance test - drinking a big 75g whack of liquid
sugar and measuring the subjects for 2 hours afterward), the fish oil group
burned 27g of fat vs. 20g in the placebo group. The fish oil group also burned
28g or carbs while storing 36g and the placebo group burned 51g of carbs while
storing only 14g.
In addition, baseline insulin was 30% lower in fish oil group and insulin responses
to OGTT were 50% lower in the fish oil group. What this tells us is that fish
oil allows the body to burn more fat and store more muscle glycogen, repartitioning
fuel away from fat cells toward muscle cells.
Since fish oils are polyunsaturated fats, it's important to not only increase
fish-oil intake, it's important to shift the ratio of polyunsaturated fat to
saturated fat (P/S). Van Marken, Lichtenbelt et al (1997) showed that the polyunsaturated
fat to saturated fat ratio is important to metabolic rate. A higher ratio of
P/S leads to metabolic increases (22% increase in TEF and 3% increase in daily
RMR).
So, if there's one thing you need to take from this section is that with all
else being equal, the fat composition (not just total intake) of your diet is
very important to your body composition. Saturated fats, while necessary to
a small extent, should only make up a small part of your diet while other fats
like olive oil, fish oil, flax oil, MCTs, and CLA all have a place on your plate.
This way you can get the same amount of daily energy from fats while gaining
lean mass and without gaining body fat.
Avoid meals containing fats and carbs
Unfortunately, this is the typical meal of the Western diet. As a result, it's
no wonder that obesity is an epidemic. Meals with a high carbohydrate content
in combination with high-fat meals can actually promote a synergistic insulin
release when compared to the two alone. High fat with high-carb meals represent
the worst possible case scenario.
Now, some people have argued that fat lowers the glycaemic index of foods and
should therefore be included in carb meals. But remember, the glycaemic index
only gives a measure of glucose response to a meal, not insulin response. And
sometimes the glucose responses to a meal and the insulin responses to a meal
aren't well correlated. So although you might be slowing the rate of glucose
absorption into the blood by adding fat to your meals, you'll promote high blood
levels of fats, carbs, and insulin. And that's a big mistake in building a phenomenal
physique and optimal health.
Eat meals containing protein and fat (with minimal carbs)
Although it's desirable to eat some meals each day that release lots of insulin,
up regulate protein synthesis, and fill up carb stores, it's advisable to avoid
too many such meals. I discussed the reasons for this above (reduced insulin
sensitivity and prevention of fat burning), but also, since we all know that
essential fatty acids are so important to health and favorable body composition,
eating protein and carb meals all day will prevent the ingestion of healthy
fats. And that's not good. Refer to the section on fats to understand more about
how essential they are to your body.
In an attempt to balance out your two or three carb plus protein (minimal fat)
meals each day, you should be eating an additional two to three meals consisting
of protein and fat with minimal carbs. Taking in 30% of each major class of
fatty acids (polyunsaturates, monounsaturates, saturates) is a good mass building
tip when thinking about which fats to consume.
Taking a step back, the purpose of protein plus fat meals is to provide energy
and amino acids without causing large, lipolysis-preventing insulin spikes.
In addition, after fatty meals that contain no carbs, the body oxidizes less
carbs (more carbs are stored and retained in the muscle as glycogen) and burns
more fat for energy. So basically you'll be burning fat for energy and storing
carbs in the muscle after such meals.
Here's a list of good fats and proteins for the protein plus fat meals:
Fats: Concentrated fish oils (PUFA-omega 3), flaxseed oil (PUFA-omega 3 and
6), olive oil (MUFA), canola oil (MUFA and PUFA), fat from nuts (MUFA and PUFA),
fat from beef and eggs, animal fat (SFA).
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