Macronutrient Timing With Consideration to Hiking

With respect to the endurance activity of hiking, macronutrient timing – i.e. the timing of ingestion of carbohydrates and protein – becomes important when the hiker is participating in continuous moderate to intense effort hiking that lasts for intervals greater than one hour’s time. The body has a finite store of glycogen in the muscle and liver (300-400g and 80-100g respectively), which permits up to a couple of hours of high intensity aerobic exercise. Thus the timing of refueling carbohydrates becomes increasingly important with proportion to the length and intensity of a particular hiking interval.

There is a particular hike in the outer reaches of Los Angeles – the trail to Mission Point from O’Melveny Park – that gets me every time! It has a 1,500 foot elevation gain over 1.6 miles with the peak being close to 2,800 feet above sea level. I get to the top and I’m starving. I come down off the mountain and my leg muscles shake in the steeper areas (yes, downhill, fatigue induced shaking). The day after, I feel like I’m getting sick; a sign of a slow recovery. It’s impossible to do in the heat. So what can I do, as far as macronutrient timing goes, to make this hike a little less harsh?

Let’s apply the International Society of Sports Nutrition’s position stand on macronutrient timing to hiking that encompasses significant intervals of moderate to high intensity. Let’s also note that this information may not be applicable or provide benefit to either hiking that is of lower intensity, or of shorter intervals (less than, say 30-45 minutes) of near maximal effort.

Carbohydrate Loading Days Prior To an Intense Hike

To saturate your muscles with glycogen before the day of an intense hike, the literature suggests that a combination of resting your muscles (no intense thru-hike training) while consuming 8-10g/kg/day of carbs is a way to accomplish this. The rest period, or period of low intensity training, should be around 3 or 4 days prior to your challenging hike, and the carbohydrate loading period would be between one to three days before your climb. I remember my father doing this before running a marathon in his early to mid 40’s; he’d eat lots of complex carbs, like whole grain spaghetti a few days before his run.

For example a 70kg male could eat 560 grams of complex carbs a day or two before they have to hit a particularly had area of the trail; this equates to 2,240kcals of carbs per day. Optimally, if thru-hiking, he’s either on an easier section of trail, or have a zero mile or near zero mile day in town. If day hiking, then he’s chilling out a home of course.

As far as female loading goes, the ISSN has this to say:

It is important to mention that due to noted sex differences related to carbohydrate metabolism and the supercompensation of glycogen stores, female athletes may need to significantly increase total caloric intake over these “loading days” to achieve effects similar to males.
International society of sports nutrition position stand: nutrient timing

Carbohydrate Loading Right Before an Intense Hike

Carbohydrate loading within the hour before participating in a long and strenuous hike is warranted, with better performance results occurring when such occurs closer to the initiation of the event than farther away, both for performance reasons, and to avoid rebound hypoglycemia, which can occur in some people, especially when using fructose. That means Gatorade would be a safer choice than Powerade. Further one study shows either a high or low glycemic carb will do the trick for this type of loading.

Carbohydrate Usage During an intense Hike

Intense hiking that lasts over an hour starts to put a strain on glycogen supplies and increases sweat rate. During this type of condition the ISSN recommends consuming carbs at a rate of 30-60g per hour, by way of a 6-8% carbohydrate solution (Gatorade is a little over 6%) using 6 oz. every 15 minutes. (ISSN’s specific stance is 6-12 oz. every 10-15 minutes, but applying the maximal possible dosage under this formula may result in a overloading of carbs, at least by their stated dosing.)

Let us further keep in mind the National Athletic Trainers’ Association’s stand on sodium repletion in fluids: if there are skipped meals before the hike, if the hike will last more than 4 hours, or if the hiker is hot weather naive, where they would naturally release more sodium into their sweat, it is recommended that fluid repletion occur with the use of fluid that has 0.3-0.7g/L of sodium. Again Gatorade falls within this realm, at 0.46g/L, but the thru-hiker would need to take a powered form of electrolyte/carbohydrate therapy with similar nutritional parameters. Proper sodium repletion is essential to avoid hypervolemic hyponatremia (you increase water in your body but not salt, making sodium levels drop, which can have neurological consequences).

Restorative Carbohydrates Immediately After An Intense Hike

If the hiker has failed to continuously supply themselves with frequent carbohydrate dosing during an intense and extended hike, they may restore glycogen within the first few hours afterward, by consuming carbs at a rate of 0.6-1g/kg within the first 30 minutes after their hike, and every 2 hours for the next 4-6 hours afterward. This method could also apply to a hiker that has completed an intense bout of hiking, are resting mid-day, and must continue forward to the next campsite, during the second half of the day.

Otherwise as long at the hiker is meeting their energy needs with the use of carbs, or is taking in 8-10g/kg/day of carbs during thru-hikes or sectional hikes that have long, intense climbs day after day, the need for rapid, post hike restoration is less necessary.

Addition of Protein To Carbs Boosts Performance and Recovery

Evidence suggests adding protein to pre-exercise carb loading, and that consumed during exercise, and directly afterward, enhances the carbohydrate’s efficacy on performance and muscle recovery, and reduces muscle damage.

Just adding a very modest amount of protein at 15 minute intervals, alongside a carb, during exercise was enough to show beneficial results. One research group used just 0.035g/kg every 15 minutes of protein to enhance a carb feeding similar to that discussed above during exercise. For a 70kg male, this works out to just 2.5g of protein every 15 minutes during the most exhaustive section of their hike, or 10g every hour of such.

One post-exercise study showed that adding 0.4g/kg of protein to 0.8g/kg of carbohydrate every hour for the first 2 hours after exhaustive cycling significantly improved next day cycling performance compared to just the carb repletion alone. This level of supplementation obliges a thru-hiker to carry some powdered supplement to achieve such high numbers of macro repletion. As discussed previously in my article on post hiking protein, using a body building protein + carbohydrate powder, in lower doses than needed for muscle building, is an easy way to get enough of these macronutrients after a hike. For the day hiker this also applies, but they have the option of downing a few cliff bars directly afterward their hike then following such up with some chicken and rice a little while later.

However post exercise carbohydrate ingestion over the 1.2g/kg/hour dosage, over 3 hours, negated the positive effects of protein, and thus for larger carb loads after hiking, a protein is less necessary, as long as one’s daily protein requirements are being met, and they are adhering to the general protein timing during their hiking days.

General Protein Timing With Regard To Hiking

I’ve covered this subject already in my protein requirements for hiking article, but here are the basics:

Evenly spaced protein meals (every 3 or 4 hours) through out the day work best on hiking days
Higher doses are required for endurance and leg muscle building type hikes (0.25 to 0.4g/kg or 20-40g with at least 10g of essential amino acids)
Higher doses are safe and effective
Protein should be consumed shortly after a major hike to ensure maximal muscle protein synthesis and repair

Fat Timing With Regard To Hiking

Currently there are no positions on the timing of fat ingestion with regard to timing. Just make sure you are getting enough essential fatty acids – that’s it!