Fat is not a bad thing. it is important for insulation (both thermal and imapct), energy, hormone production, and many other purposes, but many of us get too much of it.

As far as fueling, even the leanest athlete has enough fat stored to far outlast his/her limited carbohydrate storage and we can make fat out of any of the other macromolecules that contain energy (carbohydrate, protein, and alcohol).

At light intensity an athlete burns a relatively even mixture of carbohydrate and fat. At high intensity, we burn almost 100% carbohydrate. We need to replace the carbohydrates by eating more of them after workouts, but we don't need to worry about replacing the fat.

Overconsumption of saturated fats is till a risk factor for active people. Our risk of heart issues is dramtically reduced because of our exercise, but not to zero.

The amount of fat required for health is very, very low. Uness you are on a very extreme low fat diet, this should not be a concern.

Ken

I agree with a lot of what Ken Mierke said above here. Dietary fats are crucial for all beings, and especially endurance athletes. I unfortunately often see athletes on self-imposed very low fat diets who are often injured, sick, or if female-unable to menstruate. Saturated and trans fats do not serve any good purpose in our diets, however and should be avoided even by healthy active folks like us . Even if you are very active and not gaining weight these fats can accumulate in your arteries over time and lead to heart disease/atherosclerosis. Therefore, we should all aim for mostly unsaturated fats or “good fats” such as those from fish, avocado, nuts, olives and olive oil.
As for how much we need, that can be calculated several ways, and also depends on several factors including your current training phase and any body weight/body fat goals you may (or may not) have. As an endurance athlete, you will usually need 0.8-1.0 grams of total fat per kg of body weight per day (1 kg = 2.2#). During your race phase of your season you will want to take in higher total fat per day (but still not from trans or saturated fat). Now go eat your salad with avocado, nuts and fish-plus add some whole grains-and feel good about taking great care of yourself inside and out! :)

Lauren Antonucci RD, CSSD
Registered Dietitian Certified as a Specialist in Sports Dietetics
Member of the GSSI sports nutrition network

I believe that the fats in Perpetuem and Sustained Energy come from the Soy Protein that they have in them. I know they use Soy Isolates (which is great because it removes sugars, and prevents gas)... but Soy does also have some fat in it, so that's probably what you are seeing.

There must be something to that. Why is your immune system stronger when you have more body fat? Is it an energy issue where the immune system requires more energy?

This year's Kona race showed some top athletes succumbing and dropping out due to illness - Faris, Norman, Michelie. How much of that was because they pushed so hard while being too lean? At what point is being lean too lean? When does the loss/absence of body fat take you to an unacceptable level of risk of debilitating illness? I've read that top body builders also drop body fat like crazy to show off their muscles and that as a result, these strong men and women are the weakest and most fragile people because they can't fight off disease.

In an Olympic distance race, the ampount of fat you burn as fuel will be just slightly greater than zero. Use a drink that has water, sugar, and salt, but no fat or protein. Foods that are satiating are great for meals, but you don't want a full stomach when racing at high intensity. Protein or fat in the stomach will draw blood there, leaving less to deliver oxygen and sugar to the working muscles.

At half-rironman distance, fat is a moderately significant energy source, but don't consume fat during the event. Even the leanest athlete has plenty of fat stored to swim, bike, and run all day long. Fat in the stomach causes blood to be shunted there and delays digestion and absorption of water and sugar.

At ironman distance, some protein can be helpful, but even then keep it minimal. Even for ultra events, consuming fat is unecessary.

Ken