I’m always on a quest to pack maximum backcountry calories for minimum weight, especially during the winter season when calorie burn runs particularly high.

I’ve detailed the highest calorie trail foods out there in a previous article, Go Power: Tips for a Healthy, High-Calorie Trail Diet, but I must admit that one of my favorite go-to sources for quick, delicious energy is a candy bar. They’re inexpensive, available everywhere, and quickly add fuel to the internal furnace.

But which packs the most calories per ounce? I dug into the data to parse it out. Here’s what I found.

First of all, all chocolate-based candy bars pack a lot of calories. Almost all hover somewhere between 120 to 150 calories per ounce, so the difference between “low” and “maximum” calorie options is relatively slight, somewhere in the ballpark of 20 to 25 percent. So any candy bar is good for packing a lot of energy. That being said, here are the top 10 maximum calorie winners:

• Twix Peanut Butter: 152 calories/ounce
• Special Dark Chocolate Bar: 150 calories/ounce
• Symphony milk chocolate bar: 149 calories/ounce
• Skor: 149 calories/ounce
• Mr. Goodbar: 149 calories/ounce
• Kit Kat: 145 calories/ounce
• Hershey’s Chocolate Bar with Almonds: 144 calories/ounce
• Reese’s Peanut Butter Cups: 144 calories/ounce
• Peanut M&Ms: 144 calories/ounce
• Twix Caramel: 143 calories/ounce

A caveat here. This is a measure of calories per ounce, not the total amount of calories in each type of candy bar. This is important because the serving size varies depending on the type of candy bar, from under 1.5 ounces to just over 2 ounces. So, for example, even though a Skor bar comes tied for #3, the total bar weight is only 1.2 ounces, making its total calories per bar much less than other options.