December 26, 2018

Nutrition and food planning

Nutrition and food planning is very important, but also very difficult when it comes to multi-day hiking. Nutrition is very personal and the right nutritional balance for you depends on a range of factors. It can often take several multi-day hikes for one to be able to, to a decent precision, determine the correct amount of food required. In addition, the science around it is not set in stone, and it seems that opinion tends to dominate rather than empirically based reason. That said, I think as long as you provide yourself with enough energy throughout the day, you aren’t going too badly.

In this entry I run through some information and sources about hiking nutrition, mainly energy and protein. If you are not interested in this and just want a place to start, just jump straight to the second section.


Nutrition

Before we go into my energy and protein requirements I think it is interesting to provide some info on how proteins, fats, and carbohydrates are used by the body in relation to physical exercise. If you’re not interested in this, and just want and idea of an approach to try, skip to the next section. I have tried to keep to as reputable sources as I can whilst researching this topic, however in some cases I have had to resort to referencing website I would not completely trust as scientifically based. I have stated this where relevant.

Energy

Energy comes in two main forms: carbohydrates and fats, and one emergency resource: protein. When excess carbohydrate is consumed and not used, this will turn into fat over a longer (not well documented) time period. The muscle uses both of these energy sources during exercise.

Carbohydrates are quick to process by the muscle and provide a faster energy source, while fats are slower to process and therefore provide a slow energy source. Another key difference between fat and carbohyrdates is our body’s ability to store them: there is no limit to our fat storage, however our carbohydrate storage is ‘limited to approximately 1,800 to 2,000 calories worth of energy, or enough fuel for 90 to 120 minutes of continuous, vigorous activity’ (Endurance Sports Nutrition, 3rd Edition by Suzanne Girard Eberle.

Protein is the 3rd form of energy and this is our body’s ‘emergency energy’, the source that it will use when it has run out of its stores of carbohydrates. It is commonly used as a fuel source in the later stages of endurance exercise (Eberle, Endurance Sports Nutrition). Ideally, one would be eating sufficient carbohydrates so as to avoid this occurring. Protein is important for muscle recovery as well, and this is covered in the next section.

Energy Requirements

Nutritionist Dr. Brenda L. Braaten recommends your total energy intake should contain 50% carbohydrates, 35% fat, and 15% protein by total kJ. According to the National Health and Medical Research Council (NHMRC):

  • carbohydrates provide 16.7 kJ/gram,
  • fat provides 37.7 kJ/gram, and
  • protein provides 16.7 kJ/gram.

Converting Dr. Braaten’s ratio from kJ to grams, this gives a new ratio of roughly 60% carbs, 20% fat, and 20% protein by weight.

Total energy intake recommendations can also be found on the NHMRC site in table 3. I would expect hiking to be a physical activity level of at least 2.2. Using this table, I would expect to be requiring roughly 12,500 kJ per day, which is very close to what I have determined through experience. Using the ratios given above this would mean I am looking at 375g of carbohydrates, 115g of fat, and 110g of protein to reach my energy requirements. This fits within the carbohydrate requirements recommended by Dr Jane Read, writing for Medibank, who states 6-10g of carbohydrates per kg (i.e. for a 57kg person, this is 340-570g carbohydrates per day). As a point of interest, dietary surveys have shown that female and male endurance athletes consume 5.7 g/kg and 7.6 g/kg of carbohydrates per day (Burke, L.M. et. al., 2004).

From experiental knowledge both hiking himself and guiding others, Andrew Skurka (Book: ‘The ultimate Hiker’s Gear Guide’), recommends starting with a daily intake of 3000 calories, around 12500kJ, and then adjusting as you gain experience. Andew himself eats between 3,500 and 5,000 calories per day, however it is important to note he tends to hike 40km or more each day, which is probably more than twice what I, and the majority of multi-day hikers, would expect to do in a day on average.

A final reference is ? . According to her research, a 60kg female uses 1630kJ per hour of hiking with a light pack (a 70kg male uses 1800kJ per hour). The recommended carbohydrate intake is 5-12g/kg BM/day including; 1-4g/kg BM before hiking, 0.5-1.0g/kg BM/hour during exercise, and 1-1.2g/kg BM immediately after exercise.

Carbohydrates in recovery

It appears optimal to eat a high level of carbohydrates within an hour of finishing hiking, to replenish energy levels in the body. Athletes are advised to consume 1.0-1.2 g/kg/hr for the 4 hours following a workout (i.e. for a 57kg person this is 57-62g per hour) (Burke, L.M. et. al., 2004). I, and I expect others, am unlikely to eat multiple meals once I’ve stopped hiking, but a possible way to achieve this is by: a sports drink, eating dinner, eating dessert, and a hot chocolate. Note these are optimally absorbed when spread out in time. Personally, I often do two of these, but rarely all 4. The main message however is: try and get ingest carbohydrates within an hour, whether this is your main meal, or a snack. In his book, Andrew Skurka (The Ultimate Hikers Gear Guide) says he always eats his dessert first when he gets to camp, enough to replenish his energy and tide him over until dinner is cooked.

Protein

Protein was mentioned as an emergency energy form in the section previously, however the main reason we include high levels of protein in our diet when hiking is to help repair, maintain, and grow muscle. It seems widely accepted that protein is necessary as soon as possible after finishing exercise (aim for about about 30 minutes) to help your muscles repair the microtears caused by the exercise. WebMD states that 10-20g of protein is sufficient, and any more than that isn’t helping. Though I would take this information with a grain of salt, this does seem to align with popular belief. Note, there is no ill effect of consuming a little more protein than necessary, it simply makes food planning a little more restricted.

A somewhat more reliable source of information is the ‘International Society of Sports NutritionPosition Stand: protein and exercise’ (Jager, R. et al. 2017). I have interpreted some of the key conclusions here:

  • Added protein does not seem to increase endurance performance, but may reduce muscle soreness.
  • A daily intake of 1.4-2.0g of protein per kg per day will build and maintain muscle mass in most individuals (i.e. a 60kg person would aim to consume 84 to 120g of protein per day). Exceeding this recommendation will not provide further gains.
  • General recommendation of 0.25g of protein per kg per hour (I.e. a 60kg person would aim for 15g per hour of hiking) during endurance exercise, though this varies somewhat per individual.
  • The effectiveness of protein intake decreases the longer you wait after finishing exercise.
  • Rapidly digested proteins are most effective
  • 30-40g of casein (slow digesting) proteins before sleep helps overnight muscle recovery

It is important to note that this information is for ‘endurance athletes’, which may be somewhat more hard core exercise than hiking (at the speeds I do it anyway), but it at least provides a guide to follow. Given this information, and given I weight approximately 57kg, I plan my protein intake as follows:

  • Ensure overall protein hits 110g per day
  • Aim for 14g protein per hour of hiking in snacks. This is purely hiking time, and does not include any time taken for breaks. Easier days this is around 50g, harder days about 85g.
  • Aim for 15-20g per dinner, which should be consumed as soon as possible after finishing hiking. If 1) the hiking is expected to finish well before dinner time, 2) you prefer to set up camp before cooking, or 3) you have a low protein meal; take 15g protein powder (rapidly digesting, i.e. whey powder) to drink when you stop for camp. In this case, don’t worry about protein in the meal, it can’t hurt but is less important.
  • On difficult or long hiking days, take 30g of casein protein powder to drink immediately before going to bed.

How I food plan

There are 3 main approaches for food intake when hiking:

  1. Eat lots of small snacks throughout the day, no main meals. Though possibly the best approach for optimal absorption of energy, I don’t think I’ve ever met anyone who uses this approach.
  2. Two main meals; breakfast and dinner, with only snacks in between. You will find a lot of people recommending this approach. I have only just started using it. It provides good energy absorption levels while hiking, but still provides a structure to the day that resembles normal life. If the dinner is eaten within an hour of hike completion this can also provide optimal energy and protein intake for recovery.
  3. Three main meals plus grazing during the day. This is also very common. I used to always do this as I never thought about doing anything different to what I would do in everyday life. However, I did always feel quite ill after lunch and this provided the motivation to switch to approach 2.

The following is how I plan for option 2 or 3. Important note: I am a female weighing around 57kg, if you plan to base your food off this, make sure to scale for your body.

Daily intakes

Note: 1MJ = 1,000kJ = 239 calories

Easy Days Hard days
less than 4 hours walking, fairly flat 8 hours walking with significant elevation changes
Min. energy 11 MJ 14 MJ
Min. protein 85g 120g
Min. carbs 330g 420g
Max. weight 700g 800g

To adjust for yourself, if you skipped the previous section:

  • Daily energy requirements: see table 3 on the NHMRC site is a good place to start with for your daily energy requirements, you will adjust this as you gain experience
  • Daily carbohydate requirement: (daily energy requirement in kj) / (33.4) gives carb requirement in grams
  • Daily protein requirement: Between (1.4 x body weight in kg) and (2.0 x body weight in kg) grams.

Requirements for each meal

Breakfast

Breakfast has to be easy, lightweight, high in carbohydrates, and with moderate levels of both fat and protein. In this meal I aim for at least:

  • Less than 100g per person total weight
  • 10% total daily energy requirement, mix of carbohydrates and fats
  • 5g protein

Snacks/Lunch while hiking

Snacks and lunch should be high in carbohydrates, and provide a fairly consistent intake of protein. I avoid eating too much fat during the day as I find the slow digestion of fat affects my hiking. I split my snacks up into 100g ‘snack packs’. Often these are a combination of a salty snack that gives me a chunk of protein, and then a sweet snack to boost up the carbs. I follow the approach suggested by Andrew Skurka in ‘The ultimate Hiker’s Gear Guide’. He suggests snacks of 1650-2100kJ every 2-3 hours. For an easier hike this means 2 snack packs, for a harder hike I would take a 3rd pack. Each ‘snack pack’ has the following nutritional requirements:

  • 1700 kJ energy
  • 50g carbohydrates
  • 7g protein

In addition to these packs, I carry another 100-150g of ‘scroggin’ (for me this is 5050 maltesers and pretzels), and 50g of lollies for grazing during the day.

If you prefer to have a lunch, I used to eat the equivalent of 2-3 snack packs as a big lunch stop, and graze as mentioned above.

Snacks post-hiking/Desserts

Snacks post hiking aim to be high in carbohydrates and/or protein for recovery. These generally weight between 50g and 100g. I eat at least 1 per night equal to a minimum of 10% of my daily energy requirement.

Dinner

Dinner really wants to be high in all 3 (carbs, fats, and protein), particularly if eaten soon after the hike has finished. Each dinner aims for:

  • Less than 125g total weight
  • 20% total daily energy requirement, mix of carbohydrates and fats
  • Minimum (1.2 g x body weight in kg) carbohydrates
  • 15-20g of protein
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