The variety of fuels that Hammer offers and how we explain their best use has inadvertently caused much confusion. Hopefully, this article and accompanying video will clarify this for you and everyone else.

Back in 1992, when I introduced Sustained Energy, it was intended for our Clients engaging in long-distance, mega-endurance efforts. In the late 80s and early 90s, ultra, distance events were increasing, and there were no products designed or intended for long periods. The only available fuels were the usual sugar, citric acid, and salt combo, and they did not work for ultra distances.

However, shortly after introducing Sustained Energy, giving athletes a real ultra fuel, I realized there was a lack of carb fuels for higher intensity, shorter duration exercise. It turns out the products of the day were not working for many athletes even in these shorter durations. This led me to develop Hammer Gel and then HEED.

The introduction of Hammer Gel in 1995 and HEED in 2004 created the need to differentiate the products and their best uses. To help facilitate this, we started talking about exercise periods lasting less than or more than three hours so you would know which fuel is best based on the duration of your exercise. The introduction of Perpetuem in 2002 increased this need.

Since then, we’ve been suggesting that athletes think about fueling for their exercise bouts with a hard dividing line of under three hours or over three hours. If you exercise for 1-3 hours, use Hammer Gel if you are a water drinker, and HEED if you are a drink drinker (see my other article/video on this subject): Both are complex carb-only fuels that provide a quick boost for these durations.

However, if you plan to exercise for longer than 3 hours, Perpetuem or possibly Sustained Energy should be your primary source of calories. They contain protein, and Perpetuem even has some fat in it.

The above instructions confused many clients and even some of our staff. No one is confused about exercise lasting less than 3 hours – use Hammer Gel or HEED, and you’ll be golden. It’s the 3 + hours fueling where things get confusing. Even today, I regularly hear clients asking:

“Does that mean for my long events, I start with HEED or Gel for the first three hours, THEN switch to Perpetuem or Sustained Energy?”

NOPE. This is absolutely not what I am trying to convey.

The big idea here is that when you exercise for 3 + hours, you forego the Gel/Heed and start immediately with your protein-fortified fuel. This is super key and the big takeaway here.

After many hours, to avoid flavor fatigue, to change things up, or for more energy towards the end.


Either or both, this magical combo is for the long days.
We’re talking about 3, 6, 12, 24, 36 hours, and beyond.
The difference is both Sustained Energy and Perpetuem contain protein. Heed and Gel do not.
This is especially important because, after about 1.5 hours, your body will begin burning some protein in the gluconeogenesis process.
In fact, roughly 10% of calories converted to glycogen will come from protein.
That said, if you’re not consuming a steady protein source during these long activities, it has to come from somewhere.
By using a carb-only fuel source, after a while, your body will have to start robbing protein from… you guessed it – your hard-earned muscle mass.
This will cannibalize your precious muscle and accelerate fatigue – both of which we want to avoid.
Sustained Energy and Perpetuem are here to fill the void and help offset what you are burning.
Furthermore, Perpetuem has the Bonus advantage of having some fat to help with fat metabolism. (Read more here on ENW, all about the many benefits of some Good Fat!)


Jot this down…

Under 3 hours: HEED and/or Hammer Gel alone is fine.

3 hours or more: Use Sustained Energy and/or Perpetuem from the start.
Start sipping away 10-15 in and continuously throughout your activity.
After 6-12 hours or more, to break up the flavor fatigue, go ahead and have a little HEED or Gel for a palette perk and to get up that next hill.

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