People often ask me what's best to take out on the hill for a days walking or climbing and I've seen everything from a Mars Bar to fine hampers that would feed a primary school outing!

Lets start off with a bit of science. Food is fuel and we need enough to keep pace with our metabolism. 

In normal life Males require 2800 to 3000 KCal per day, whilst females require 2000 to 2200 KCal. The more active we are the more we need. An ascent of Snowdon via the PYG Track would require an additional 1200 KCal approx. 

Polar explorers can burn over 7000KCal per day and still lose weight!

The older you get the slower your metabolism, and of course it varies between individuals. 

So here are some tips:

1. Never miss breakfast, it really is the most important meal of the day. Ideally make it a high carbohydrate meal - porridge is ideal. 
2. Eat like cattle - graze rather than have big meals. You need to take on board complex carbohydrates that will release energy slowly. Good examples are cheese sandwiches, flapjacks, pasta, dried fruit. 
3. Avoid chocolate and fizzy drinks. They will just give you a short term sugar high, followed by a low which feels awful. 
4. Drink plenty of water. 2 litres in cool weather, upto 5 litres in hot weather. 
5. Eat your evening meal within 2 hours of coming off the hill and make sure its big and well balanced. ie fresh vegetables, protein, carbs, fat. 
6. Avoid caffeine  - it is a diuretic which means you will pee more and so de-hydrate. 

What I take in my sack depends on the time of year but will generally consist of a few cheese sandwiches, some cereal bars, flapjack, apple, banana, dried fruit and nuts and then in the winter a flask of hot chocolate. I am a skinny devil and really struggle if I don't eat enough. I look forward to sharing your lunch!