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Replace What You Lose or What You Can Assimilate?
How to Fuel Successfully

Perhaps the biggest challenge we at Hammer Nutrition face is convincing athletes that the “replace what you lose” theory of endurance fueling is completely ineffective and one that needs to be eliminated if better results are to be achieved.

HINT: Less IS Better Than More!

What we’re talking about are the “experts” and organizations recommending that athletes need to consume what they lose during exercise in equal to near-equal amounts. They drum up statistics such as “you lose up to two grams of sodium per hour, burn up to 900 calories hourly, and sweat up to two liters an hour” to defend their position. Even worse is that, in many instances, they don’t give any numeric guidelines, just vague statements like “drink as much as you can”. Sadly, far too many athletes fuel their bodies exactly this way – based on the recommendations of what one elite athlete may be using and/or saying – with only poorer-than-expect results or a DNF to show for their efforts.

What these “experts” don’t take into account when making these “replace what you lose” recommendations is that how much you’re losing – fluids, calories, and sodium – is totally secondary to what you can effectively replace. In other words, what you are burning/losing is not what you should be focusing on, but rather what the body can reasonably assimilate during any given period of time. Two statements by Dr. Bill Misner represent our position on what proper fueling is all about:

“To suggest that fluids, sodium, and fuels-induced glycogen replenishment can happen at the same rate as it is spent during exercise is simply not true. Endurance exercise beyond 1-2 hours is a deficit spending entity, with proportionate return or replenishment always in arrears. The endurance exercise outcome is to postpone fatigue, not to replace all the fuel, fluids, and electrolytes lost during the event. It can’t be done, though many of us have tried.”

“The human body has so many survival safeguards by which it regulates living one more minute, that when we try too hard to fulfill all its needs we interfere, doing more harm than good.”

What this means is that the body cannot be replenished at the same rate that it becomes depleted. Yes, the body needs your assistance in replenishing what it loses but that donation must be in amounts that cooperate with normal body mechanisms, not in amounts that override these crucial mechanisms. Here’s an important fact to keep in mind (paraphrasing Dr. Misner) - At an easy aerobic pace, the rate of metabolism increases from a sedentary state to a range of 1200-2000%. As a result, the body goes into “survival mode” where blood volume is routed to workout working muscles, fluids are used for evaporative cooling mechanisms, and oxygen is routed to the brain, heart, and other internal organisms. Interestingly, it NOT focused on calorie, fluid, and electrolyte replacement, as some of the “experts” advise.

In other words, the body already “knows” it is unable to immediately replenish calories, fluids, and electrolytes at the same rate it uses/loses them, and it deals with this issue by releasing specific hormones that compensate for all but about 20-30%, which can be replenished orally. That’s why we don’t recommend trying to replace hourly losses of calories, fluids, and electrolytes with equal amounts, but instead recommend a smaller replenishment donation, one that cooperates with normal body mechanisms.

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Some Common Fuel-Related Characteristics of Poorer-Than-Desired Performances

Fluid intake is nearly always over 30 ounces/hour

Body weight at finish is hyper-hydrated with weight gain above 1-2%

Body weight at finish is dehydrated with weight loss over 3%

NOTE: Weight loss or gain of over 2% leads to hyponatremia problems.

Excess calorie consumption, especially from simple sugar fuels, which raise osmolality in the gut, forcing the body to pull electrolytes out of an already electrolyte-depleting system, causing stomach shut down.

Excess sodium from diet and/or during-exercise intake.

NOTE: Not only are high sodium diets bad for your health but those who consume high amounts of sodium in the diet are guaranteed greater sodium loss rates and require greater sodium intakes during exercise. Sodium, as you know, drives thirst and thirst drives drinking until excess results… not a good scenario.

Our Basic Recommendations

• Fluids – 20-26 ounces hourly
• Sodium Chloride – 300-600 mg hourly (3-6 Endurolytes capsules)
• Calories – 240-300 calories hourly

There are many individual variations that you will need to consider (age, weight, training/racing stress, fitness, acclimatization levels, weather conditions) to determine what works best for you. However, these are the amounts – the “gauges” if you will – that are a good starting point for you, amounts we feel will serve you the best in your workouts and races.

The bottom line is that if you hope to achieve better results in your workouts and races, and if you want to greatly decrease the opportunity for a whole host of maladies from occurring, you need to ditch the “replace what you lose” concept and adopt the “fuel in cooperation with your body” concept.

Steve Born, Technical Advisor
E-CAPS

Steve Born is a technical advisor for E-CAPS with over a decade of involvement in the health food industry. He has worked with hundreds of athletes - ranging from the recreational athlete to world-class professionals regarding their supplement/fueling program. Steve is a three-time RAAM finisher, the 1994 Furnace Creek 508 Champion, 1999 runner-up, the only cyclist in history to complete a double Furnace Creek 508, and is the holder of two Ultra Marathon Cycling records. In February 2004 Steve was inducted into the Ultra Marathon Cycling Hall of Fame.

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