It's customary to have lots of leftovers at Christmas, and what a wonderful custom it is. After the big day, we get to cook up all sorts of things: turkey soup, turkey curry, turkey stir fry, turkey pavlova, turkey vodka. We re-fry roast potatoes in leftover goose fat, chop up mince pies to swirl through vanilla ice cream - and oh, the endless potential for sandwiching! It's so exciting I've turned it into a verb.

But what if, instead of eating your leftover festive bounty off such pedestrian things as bowls and plates, you took them up a hill or out to the crag and ate them out of tupperware and tinfoil?

How good is a leftover roast potato on the 28th of December when you're desperately trying to counter the festive excess with some fresh air and zone three huffing and puffing? Is a slice of Christmas pudding just too boozy for a mid-Munro snack? Well, in the name of scientific tomfoolery, me and my daft mates have decided to determine, once and for all, what the best leftover festive hill food is, including all those sweet treats that always seem to be floating about over the holidays.

A few alcoholic spoonfuls now and again as you feel yourself lagging will perk you right up

The criteria are the same as determining what makes a good hill-snack in winter: portability (including whether you can eat it with gloves on), calories for weight, edibility at below zero, and most importantly, deliciousness. 

Leftover roast potatoes

These were a great idea in theory, but in practice they had lost their straight-from-the-oven crispiness, and the inside was actually too fluffy, getting caught in your throat a wee bit as you chewed.

Of course, they're nice and portable if you wrap them in foil or pop them in an old yogurt pot, and due to an abundance of saturated fat they offer relatively good calories for their weight. But they're definitely let down by the texture. Waxy new potatoes work a lot better cold than your starchy Maris Pipers, so these scored slightly lower than I expected for such a God-tier part of Christmas dinner. 

• Portability: 8/10
• Calories for weight: 6.5/10
• Below zero edibility: 7/10
• Deliciousness: 4/10
• Score: 25.5/40 

Extra thick brandy cream

This is something a lot of people seem to have left over at Christmas, so why not take it up the hill? It's utterly delicious - and sessionable if you're trying hard enough, coming in at 3.7% alcohol by volume. It also offers an abundance of energy, with a 250g pot giving you just over 1000 calories.

Can you eat it all in one sitting? Yes. Should you eat it all in one sitting? No, not unless you want your gall bladder to explode.

It turns out shoving a large amount of ice-cold mincemeat straight into the old mouth-hole isn't all that pleasant

It's extraordinary rich. But don't let this deter you - a few alcoholic spoonfuls now and again as you feel yourself lagging will perk you right up. It also has the added advantage of basically becoming ice cream at very low temperatures, which is never a bad thing. If you do decide to bring it with you though, you're best sliding the whole tub into a portable coffee cup with a well-fitting lid, because there's no way of resealing it once it's open, so it does lose points for portability here. You'll also need a spoon, which adds to the faff.

• Portability: 4/10
• Calories for weight: 9/10
• Below zero edibility: 9/10 
• Deliciousness: 7/10, decreasing with amount consumed
• Score: 29/40

Mince pies

These were another slight disappointment. I usually make my own mince pies because I use a buttery orange and almond pastry which is a lot lighter than the cardboard clagginess of most shop-bought ones - but it was actually the filling that let the side down here.

It turns out shoving a large amount of ice-cold mincemeat straight into the old mouth-hole isn't all that pleasant. So while they're relatively portable, and at 230 calories per pie, offer a good amount of energy to power your winter walking, they're losing mega points for deliciousness and below-zero edibility. Definitely one to eat warm from the oven with some of that brandy cream rather than lug up a hill at minus 2. 

• Portability: 7/10 (loses points for being squishable)
• Calories for weight: 8/10
• Below zero edibility: 3/10
• Deliciousness: 4.5/10
• Score: 22.5/40

Brussel sprouts

As a rule I don't boil vegetables. Brussel sprouts have an awful reputation for basically becoming fart flavoured sogg-balls when thrown into hot water, so I usually shred them raw and stir fry with harissa paste instead (but please don't tell my Gran). However, catering to a more normal idea of what brussel sprouts look like meant I steamed these ones in the microwave and coated them with soy sauce before bunging in tupperware to take walking.

They were, erm, manageable. To be fair to them, they were almost refreshing after eating half a tub of that brandy cream. But overall, it's best to leave leftover sprouts at home to roast them with diced chorizo, hot sauce and good olive oil so they go nice and caramelised. Don't take them up Cairngorm in late December and expect to enjoy them. 

• Portability: 6/10 
• Calories for weight: 3/10
• Below zero edibility: 5/10 (they're more watery than a lot of the stuff here, so go somewhat slushy)
• Deliciousness: 4/10 (if I'm being generous) 
• Score: 18/40

Lebkuchen hearts

Someone always brings lebkuchen hearts to your house over Christmas, and for good reason: they're cheap compared to most other festive treats. For me, they're definitely middle-of-the-road when put next to things like yule logs and christmas biscuit selection boxes, but they're actually great hill fodder as their chewy-yet-cakey texture means they don't fall apart when you so much as look at them.

It helps that they're coated in chocolate (disclaimer: you could coat cufflinks in chocolate and I'd still have a go at eating them) and they're nice and easy to get in and out of a jacket pocket too. Overall, a very good bet if you're taking something else savoury with you too, because the vast amount of calories here are from carbs, most of which are sugars, so they're not as sustaining as other things. 

• Portability: 9/10
• Calories for weight: 7/10
• Below zero edibility: 8/10
• Deliciousness: 8/10
• Score: 32/40

Pigs in blankets

Now we're talking. These were by far the most popular item amongst my meat-eating friends, and served as a deeply savoury respite from the deluge of sweetness offered by most festive hill-snacks. I don't need to explain that wrapping sausagemeat in smoked streaky bacon is an excellent idea, and I probably don't need to mention that they're relatively calorically dense and actually include something in the way of protein. The only thing you need to do is cook them beforehand, which takes away a point for portability, but other than that, they're pretty perfect - that is, if you're not veggie or vegan. 

• Portability: 9/10
• Calories for weight: 8/10
• Below zero edibility: 9/10 (they're very tasty cold)
• Deliciousness: 10/10
• Score: 36/40

Christmas cake

Christmas cake is perhaps the most leftovery of leftovers, as who on Earth is going to fit a boozy slice of fruitcake in after smashing through a family box of Ferrero Rocher, followed by Christmas dinner, Christmas pudding, and a cheeseboard? Happily, Christmas cake keeps excellently so is brilliant for taking with you into the mountains, even late into the New Year if you've managed to keep it around for that long. Portability-wise, it's not as crumbly as other cakes, so squishes down well into some foil or clingfilm. Essentially, it's festive Soreen, so keeps you going with a good amount of energy from dried fruit and candied peel, plus a staggering amount of fibre to keep you full. However, I have knocked off a point or two for deliciousness since a large percentage of the adult population can't abide it. 

• Portability: 8/10
• Calories for weight: 8/10
• Below zero edibility: 9/10
• Deliciousness: 7.5/10
• Score: 32.5/40

Salmon pate and crackers

Salmon paraphernalia seems to get thrown around a lot at Christmas: smoked salmon canapes, smoked salmon with cream cheese on blinis, salmon en-croute, and yes, if you're a skintflint like me, salmon pate with oatcakes.

We caught this one in the wild, and happily it came with a lid so you could reseal it, so it wins points on portability. It's a very delicious thing to take up the hill with you, but at only 193 calories per 100g, it's not massively energy dense - even paired with a packet of oatcakes at 225 calories, it still pales in comparison to fruitcake in terms of energy to weight ratio. Plus it's not so easy to eat with gloves on. 

• Portability: 7/10 
• Calories for weight: 6/10
• Below zero edibility: 7/10 (it just gets a bit more viscous below freezing, which is still fine for scoopage)
• Deliciousness: 9/10
• Score: 29/40

Christmas pudding

Having lived in Scotland for five years, my first thought when I looked at this Christmas pudding was how fabulous it would be if you cut it into slabs, battered it, deep fried it and served it hot with vanilla ice cream and a dusting of sugar.

When I stopped salivating and came to the realisation that this would be very difficult to execute outside, even on a low-level amble, I was slightly disappointed. But upon eating it cold, I realised that Christmas pudding is basically a more portable, denser, boozier version of Christmas cake - and as a plus, it's half the price. The one I bought from Co-Op happened also to be vegan, and came in at just under 1300 calories for the whole thing - more than enough to keep you going for a snowy uphill foray if you were tight on time and effort.  

• Portability: 10/10 if you cut it into slabs before you go (don't pick at it from the tub with the arse end of an ice-axe)
• Calories for weight: 9/10
• Below zero edibility: 9/10
• Deliciousness: 7/10 (was slightly too boozy for some)
• Score: 35/40

Cheeseboard (skeeseboard)

There's often enough cheese at Christmas to sink a mouse, and much of it doesn't get eaten on the big day for various selection-box shaped reasons.

If you've got enough of it left over to make a miniature cheeseboard for the hill, do bring it all along and sit down at the top for a sophisticated luncheon, weather allowing. Bonus points if you bring a chopping board with you, but this will obviously decrease the calorie-to-weight ratio. We got around this by using a ski as a stylish way to share our delectable platter. Needless to say that crackers are a must with this, and if you can bring grapes, that'll heighten the enjoyment too.

• Portability: 6/10
• Calories for weight: 8/10
• Below zero edibility: 7/10
• Deliciousness: 9/10
• Score: 30/40

Quality Street

Everyone gets a bit fed up with Quality Street by the end of the holidays, so instead of mindlessly grazing on them when you don't really need to, why not set some aside to take on your next walking trip?

I'm not going to pretend that they're nutritionally brilliant, but they're a nice wee treat to stuff into pockets here and there, and make good bribes for reluctant children too (hi, it's me, I am the reluctant child). The only thing I'd recommend is stuffing the toffee pennies and suchlike into a pocket close to your body so you don't break your teeth on them when it gets chilly. 

• Portability: 9/10 (they lose a point for being difficult to unwrap with gloves on)
• Calories for weight: 8/10
• Below zero edibility: 8/10 (the fondant creams are great into the minuses, but points are lost for the toffee-containing ones)
• Deliciousness: 7/10
• Score: 32/40

Conclusions

It turns out pigs in blankets and Christmas pudding are the best things to take up a snowy hill with you, with the Piggy Bs just inching ahead with a score of 36 over Christmas pud's 35. But really, it's great to mix up your hillwalking snacks at Christmas in any way you can, so take a little bit of everything and enjoy the mountaintop novelty of eating a whole roast dinner out of a ziplock bag followed by a slice of Christmas pudding to dip in your brandy cream. It beats a cheese and pickle sandwich any day.