Choosing between Sustained Energy and Perpetuem is really based on your personal preference.
Sustained Energy - This is our time-tested standard fuel for extended exercise. As explained in other articles in this handbook, any exercise beyond about two hours requires a protein component in the fuel. Sustained Energy contains about 87% carbohydrates (almost all from maltodextrin and glucose polymers-no added simple sugars, of course), and about 13 % isolated soy protein (7:1 ratio), the ideal combination to use when rate of exercise is between 70-85% MHR in "sustained" efforts lasting anywhere from 3-12 hours.
Perpetuem - This newer product takes the concept of long-distance fueling to the max. We designed it primarily for extreme endurance events lasting about six hours to many days. Perpetuem contains 75% carbohydrates (from long-chain maltodextrins-no added simple sugars), 13% fatty acids from a specially made long-chain lyso-lecithin, and nearly 10% soy protein. A small portion of fat seems to cue your body to more liberally release its fatty acids stores, which account for up to 70% of one's energy requirements in long bouts of exercise. A little fat in the fuel also slightly slows the rate of digestion and thus promotes "caloric satisfaction," another attractive plus during primarily aerobic ultra-long distance events. Perpetuem provides maximal benefits at an aerobic pace (under 70% MHR).
- Sustained Energy is a neutrally flavored powder. Perpetuem comes in strawberry-vanilla, orange-vanilla "Dreamsicle" and caffe latte flavors.
- Perpetuem contains lyso-lecithin fat, whereas Sustained Energy does not.
- Perpetuem contains tribasic sodium phosphate, which is a tremendous lactic acid buffer. Sustained Energy does not contain this nutrient.
- Both fuels contain l-carnosine (an antioxidant that also buffers lactic acid) l-carnitine (to promote fatty acid utilization), and chromium polynicotinate (to stabilize blood sugar level).
- Perpetuem contains the new "XT" soy protein preparation, which, along with the sodium in tribasic sodium phosphate, provides a more complete mineral profile. The mineral content in a two-scoop serving of Perpetuem may allow you decrease your Endurolytes intake by one capsule per hour. Also, the "XT" soy protein contains higher isoflavone content, believed to have superb cardiovascular health benefits. Sustained Energy has soy protein and an excellent isoflavone content, but the strain used in Perpetuem has even more.