Barefoot TJ wrote:Olive oil,
Barefoot TJ said:
Olive oil, avacados, nuts, etc., are all natural foods and very high in fat (good fat, but it's still fat, correct?). Eating an abundance of any of those don't contribute to fat build up? Explain.
TJ- was that a troll? Did you just KNOW I was itching to 'splain?!?
Basically, yes - fat contributes to fat build up.
Ingested fat facilitates a variety of metabolic processes. What isn't used is subsequently stored as fat, which can later be used to fuel activity.
Ingested carbohydrate facilitates a variety of metabolic processes - among other things, it can give a fairly rapid boost to blood sugar that is "immediately" available to be burned as fuel and (IIRC) some of it might contribute to replenishing glycogen stores. What isn't used is subsequently stored as fat, which can later be used to fuel activity.
Carbs sound like a great thing at first blush - why not burn some now and then store what's uneeded as fat?
Well... that sugar is cheap and easy fuel for your body. When present, your body will go for it first and (largely) skip burning any of the nagging fat that you may have hanging around.
And... the other thing that carbs (aka sugar) do (to varying degrees, based on source/type) is trigger the insulin response. That is, as blood glucose (sugar) rises, insulin is released in response. Insulin is what helps move the glucose into muscle & fat cells for storage. The insulin level peaks after the blood glucose level peaks and is returned to normal. In essence, the insulin is lingering, looking for something to do - that is, more sugar to process. What results is increased hunger, wobbly knees, often the desire for more sugar.
So, you can see that the body's gotten itself into a vicious cycle and is becoming a well-padded, sugar-craving machine.
Why would "low-fat" be a bad thing?
Well, sometimes there's a reduction in calories, which might not be all bad. But, often the fat is replaced with something carb-rich instead - thus further contributing/increasing the insulin response. (An example of a substitution might be replacing eggs in a baking recipe with yogurt. The yogurt [potentially] has lower fat, but the lactose in the milk/yogurt is...sugar!)
Another downside to "low-fat" is that, without fats, certain nutrients in the food won't be as readily absorbed by the body (if at all) - so, you're missing out on some of the nutritional goodness of that "healthy" low-fat food.
What to do?
Eating a combination of carbs, protein, and fat can help blunt the insulin spike. Additionally, choosing carbohydrates with a lower glycemic index and - EVEN MORE BETTER - lower
glycemic load will also help tame the insulin monster.
(Glycemic Load considers the effect of a portion of food - ex: watermelon has a high glycemic index, but pretty low carb content by weight (it's mostly water!), so its overall effect can easily be less than that of a similar portion of a lower GI food... hence, low glycemic load)
For a person living a low- to moderately-active lifestyle, our liver is capable of creating enough glycogen from our body fat on a daily basis to MORE than get us through the day. (Assuming activities are, more or less, kept to low intensity and are truly aerobic.) As length or intensity of activity increases (think a few hours of Maffetone-style low heart rate running or fast racing/sprinting) the body will need more glycogen - this, it will need to get from ingested carbohydrates. It is also possible to train the body to become a more efficient and willing fat burner, shifting the balance of energy that comes from fats & carbs (and, yes, we do burn both at once - but the ratio varies); this is done by increasing one's aerobic capacity/efficiency.
Phil Maffetone and
Mark Sisson have more info - supporting similar (but NOT the same) diet and training ideas.