Pop-tarts are the epitome of junk food, aren’t they? A white-flour based crust that leaves behind a white residue on your fingers making it look more like you just finished up an intense game of pool rather than having breakfast. They're lathered with a thick crust made from sugar so hefty even a turtle would be envious of its structure. Oh, it doesn't stop there. The "fruit" filling is more like a spackle you'd slather around the drywall patch in that fixer upper your wife convinced you to buy as your first home… but man are they delicious!
How does something that seems like complete garbage show up as a fuel source recommended by a dietitian?
The Driving Force Behind Muscular Demand
Muscular demand is ultimately what dictates whether a carbohydrate is good, bad, or neutral. Consequently, it's also a major predictor of whether calories that come from carbohydrates ultimately lead to you gaining weight, losing weight, or maintaining your current weight.
The graph below explains the complex nature of muscular demand, healthy food, and carbohydrate intake. In short (and assuming two foods match calories, carbohydrates, fiber, protein, fat, etc.), if your body needs it, it's going to use it as fuel. It doesn't matter if the carbohydrate source is from a "healthy food" or something that seems like complete garbage-like Pop-tarts
Why the emphasis on carbs?
It's been emphasized time and time again that not having a solid nutrition plan or focusing excessively on fats and proteins in the mountain will work, but I've almost always followed that statement up by clarifying that our aim isn’t to help folks just experience nutrition that works; we want them to see what a difference a day in the mountains can make when they have a nutrition plan that is dialed in, tailored to them, and has the right amount of carbohydrates balanced with their activity level. Here is why.
Fats and proteins work, but they take a much longer time to produce the primary energy/driver for muscles in high output activity-glucose. It does not make much sense to eat something that takes significantly longer to "reach" you when there is an alternative that can be metabolized almost immediately and give you the energy needed to reach the peak in front of you. This graph does a great job putting this premise into a visual context. (Disclaimer: the example is hypothetical with times that are also hypothetical. It’d be incredibly difficult to show a graph depicting how fast people break down nutrients because a number of factors cause people to metabolize nutrients at a different rate).
One of the most obvious trends in the graph is that carbohydrates tend to start taking a dip in available energy at about hour three. It’s because of this that we strongly advocate you’re eating regularly and often to replenish the used fuel and keep the trend line between the 80-100 percentile. Many “fat is fuel” advocates would say this reason alone is why you should eat a high fat diet - it provides the most energy. It does produce the most energy overall (look up “ATP” in your search engine of choice), but it does not produce the most available energy in the quickest amount of time. Total energy yield really doesn’t matter if it’s not “in the tank” for you to use.
Don't get caught up in comparing the two graphs. Both are hypothetical examples that are meant to show trends rather than nitty-gritty numbers of a real person. The main takeaway is this: carbohydrates are the most readily available source of energy and primary energy source during high-output activities like hiking.
An athlete, hunter, or anyone in pursuit of outdoor adventure meets the sweet spot when the demand of the muscle is matched with adequate intake of carbohydrates. Because the body burns that fuel so quickly, there is no time for "garbage" to sit around and cause the effects we normally associate with "junk food". This is why Pop-tarts are considered an excellent fuel source in the mountains.