Zone 2 training & calories from carbs v body fat

Triathlon Forum
1

So there’s plenty of info regarding how many calories to consume per hour during races by body weight and intensity. That’s great.

I cannot find any info on what type of consumption rate you should follow for long zone 2 training though. It’s lower heart rate and should be in the body fat burning range. Lord knows I have plenty.

I bonked pretty hard in the last 15 min of a 3 hour zone 2 training ride today. Had a granola bar before and a stinger waffle mid ride. Clearly wasn’t enough, but in all zone 2 and a mild amount of zone 3, shouldn’t I be able to rely almost exclusively on body fat since I’m not working at a primarily sugar burning heart rate?

If not - what type of calorie consumption are you guys following for long low rides?

2

For my 3+ hour rides I take just water for the first hour or so then I just follow my normal 300 or so calories an hour for the rest. I’ll carry some 911 gels and money for a Coke if I feel like I’m getting cloudy in the head. I don’t really believe in that train on empty or low crap, maybe for something easy first thing in the morning, but anything quality to include an endurance ride, no.

3

Unless I’m trying to lose weight once I get into my longer training sessions I try and mimic race day nutrition. I think usual ranges are 350-450 cal/hr on the bike then 150-250 cal/hr on the run. On the bike you’re basically trying to make sure you have some fuel coming off the bike so you’re taking in more. Over the course of several long training days you should be able to dial it in fairly well.

If you’re really trying to adapt to fat from what I understand (a) it takes time and (b) you’ll likely have some bonks along the way.

4

I would also say that it is hard to workout for 3 hours without taking in a decent amount of nutrition. Also, you are probably NOT burning majority fat for fuel if your training in the top half of zone 2 to zone 3. Generically, the state where your body is burning >50% fat for fuel is low to mid zone 2 or anything below that. It also depends how fat adapted your body is…

5

Not trying to adapt per se, but happy to have some form of fat adaptation. Separately, also interested in weight loss during this base period, but definitely not at the risk of a shitty training session. Sounds like I probably just under consumed. I’m a big guy, so I burn a ton during workouts and probably could have consumed another 300-400 calories and still been at a large deficit. I just don’t want to consume more sugar than necessary if there’s an opportunity to nurture an adaptation. Training for an IM, so it would be nice not to live off of stinger waffles and Gatorade for 14-15 hours.

6

Not trying to adapt per se, but happy to have some form of fat adaptation. Separately, also interested in weight loss during this base period, but definitely not at the risk of a shitty training session. Sounds like I probably just under consumed. I’m a big guy, so I burn a ton during workouts and probably could have consumed another 300-400 calories and still been at a large deficit. I just don’t want to consume more sugar than necessary if there’s an opportunity to nurture an adaptation. Training for an IM, so it would be nice not to live off of stinger waffles and Gatorade for 14-15 hours.

I fuel with a half peanut butter and honey sandwich every hour, plus water with nuun tabs.

Then when it gets closer to the race, I practice race day nutrition. It seems to work. Gets my body used to running on not too many calories. I do this after hitting the wall 22 miles into a marathon and barely finishing.

My body is pretty adapted to stresses of running 2 hours with no nutrition and biking 3 hours with no nutrition when I try it.

7

So you had 400 calories or less for a ride that likely burns 2100 or so calories (250 bar and 150 Honey Stinger).
You probably could use more like 600-800 on the bike, plus a decent breakfast, plus a decent recovery meal.

Unless you are in the ketosis camp (and eating and training accordingly), you need to fuel your training and recovery.
If not, you will ride slower, and take longer to recover.

Look at your daily caloric needs- Try to create a 300-500 calorie deficit for the entire day.

Unless you are small and put out little power, a ride like this makes it a 4000+ calorie day.

8

IMHO it’s just lack of fitness, Zone 2 on a bike for three hours is not enough to need food.

I think in general people eat far too much during training. When they struggle, it’s hydration, nutrition, weather - anything but lack of fitness that could be the cause.

To give you an idea, at the moment I do my weekly long runs of 20miles in Zone 2 HR (140bpm, max is 198bpm)

This morning, I had a coffee before going out, and no food or water on the run, which lasted 2hrs45min. HR stayed the same throughout (TrainingPeaks said 0.5% decoupling).

A few months ago I didn’t have the same fitness and would have exploded for sure after 10 miles or so. But that’s fitness not food.

If I have to push in Z3 up threshold, yes, I need a gel every now and then.

9

Lose weight in the kitchen, not on the bike.

3 hours easy is more than enough to bonk. I’ve bonked 30 minutes into a recovery ride when I was just totally glycogen depleted. Your body needs glycogen.

10

Two totally conflicting responses. I think that’s where my confusion lies for sure.

No doubt fitness isn’t great yet. To answer an earlier question, no I’m not interested in keto.

I interested in not consuming a massive buffet meal on the bike during an IM and then running a bloated marathon feeling like I’m going to crap myself the whole way. I suppose that why we practice nutrition in training though, to see what works.

11

Two totally conflicting responses. I think that’s where my confusion lies for sure.

No doubt fitness isn’t great yet. To answer an earlier question, no I’m not interested in keto.

I interested in not consuming a massive buffet meal on the bike during an IM and then running a bloated marathon feeling like I’m going to crap myself the whole way. I suppose that why we practice nutrition in training though, to see what works.

That’s why I like my PB & Honey sandwiches. With wheat bread, one has around 200 calories. 70 for bread. 90 for the PB. 40 for the honey. It’s a good mix of simple sugar, slower carbs, fat and just a hint of protein. And it is real food which makes me happy.

This way, I am not feeling with pure carbs and when I need the pure carbs my body processes them really well.

12

please read Ben Greenfield book

https://www.amazon.com/Low-Carb-Athlete-Low-Carbohydrate-Nutrition-Performance-ebook/dp/B015M1MHFC
.

13

I can usually manage a 3 hour ride without food, but for recovery it is always better that I do.

I will always have a bottle of perpetuem if the ride is longer than 3.5 hours. And I will always have 1 cliff block shot for every hour of riding. So a 4 hour ride will have me bring 4 cliff blocks and 1 bottle of perpetuem. If it is going to be a 5+ hour ride I will usually bring a little container with some extra perpetuem for an extra bottle.

I will try to eat after each hour, or shortly after a bigger effort (say I just reached a peak on a climb). I alternate drinking my mix and water as I find that sticking solely to my mix gives my stomach fits.

14

I bonked pretty hard in the last 15 min of a 3 hour zone 2 training ride today.

shouldn’t I be able to rely almost exclusively on body fat ?

there’s your answer

15

How much water did you drink?

I would be taking into account the fact that everyone burns fat differently at different levels of intensity. While someone who is fit and well fat adapted might burn a huge % of fat in zone 2, maybe with the shape you’re currently in you can’t. Unless you want to do the appropriate testing to see where your crossover point is I’d suggest taking some extra food on your next ride.

16

I’m going to skip over Total Caloric Expenditure per hour or this would be very long.

Moving straight into Fat & carbohydrate ratios and how much to consume.

Assumptions: Normal, well-fed MALE who is not in glycogen depletion or has any metabolic disorders etc.

Fat vs Carbohydrate Ratios

By Threshold we can assume 100% of energy is from CarbohydrateThe highest rate of fat metabolism typically corresponds to the first lactate turn-point or the upper end of Base / Zone 2 / etc. More fit individuals have higher maximal fat oxidation Broad Recommendations (Individuals WILL vary)

4.0w/kg @ threshold riders and above:
50+% fat contribution at the top of zone 2. ~0+% at threshold 3-4w/kg riders
~30% fat contribution at zone 2 0% contribution at threshold 3.0w/kg and below
~20% (or below) fat contribution at zone 2 0% contribution by 90% of threshold.
For Example:

Rider - Threshold ~3.5 watts / kgUpper limit of “Base” = ~210 watts Gross Efficiency = ~21.5%
Total Kcals / Hour ~890 CHO Contribution = 70% = ~580 kcals/hrFAT Contribution = 30% = ~310 kcals/hrCHO Storage

We have approximately 1,000kcals of glycogen stored in our lower body
(upper body storage is not useful for cycling as it’s locked in the muscle).We have an additional approximate 450kcals in our liver.
This maintains our blood sugar and is rarely fullThat’s ~1,500 kcals (Or less) to play with for an average sized male.

CHO supplementation
Total needed CHO supplementation = CHO Storage - (Planned Riding Time (hrs) x CHO Kcals / hour)

For example:

1,500kcals - (1 hour x 580kcals) = +1,000kcals stored
NO Need to supplementation1,500kcals - (2 hours x 580kcals) = +340 kcals
Probably fine without supplementation but almost empty. A little something adds security1,500kcals -(3 hours x 580kcals) = (-240kcals)
Need to supplement with at least 240 kcals for *optimal *performance (e.g. little to no power loss)Your situation is similar to #3. You took in approximately 200kcals during the ride. Which should have left you with basically nothing in the tank at the end of your ride, which is essentially what you experienced.

If glycogen stores were not completely full due to daily training; less storage = bonk more likely Some time spent above zone 2 = faster CHO oxidation = bonk more likelyTaking CHO in drink = bonk less likely

Disclaimers:

  1. Everyone is an individual, actual numbers will vary
  2. I didn’t necessarily do all the math, the numbers are close enough for illustration, but rounded for simplification
17

I’m going to skip over Total Caloric Expenditure per hour or this would be very long.

Moving straight into Fat & carbohydrate ratios and how much to consume.

Assumptions: Normal, well-fed MALE who is not in glycogen depletion or has any metabolic disorders etc.

Fat vs Carbohydrate Ratios

By Threshold we can assume 100% of energy is from CarbohydrateThe highest rate of fat metabolism typically corresponds to the first lactate turn-point or the upper end of Base / Zone 2 / etc. More fit individuals have higher maximal fat oxidation Broad Recommendations (Individuals WILL vary)

4.0w/kg @ threshold riders and above:
50+% fat contribution at the top of zone 2. ~0+% at threshold 3-4w/kg riders
~30% fat contribution at zone 2 0% contribution at threshold 3.0w/kg and below
~20% (or below) fat contribution at zone 2 0% contribution by 90% of threshold.
For Example:

Rider - Threshold ~3.5 watts / kgUpper limit of “Base” = ~210 watts Gross Efficiency = ~21.5%
Total Kcals / Hour ~890 CHO Contribution = 70% = ~580 kcals/hrFAT Contribution = 30% = ~310 kcals/hrCHO Storage

We have approximately 1,000kcals of glycogen stored in our lower body
(upper body storage is not useful for cycling as it’s locked in the muscle).We have an additional approximate 450kcals in our liver.
This maintains our blood sugar and is rarely fullThat’s ~1,500 kcals (Or less) to play with for an average sized male.

CHO supplementation
Total needed CHO supplementation = CHO Storage - (Planned Riding Time (hrs) x CHO Kcals / hour)

For example:

1,500kcals - (1 hour x 580kcals) = +1,000kcals stored
NO Need to supplementation1,500kcals - (2 hours x 580kcals) = +340 kcals
Probably fine without supplementation but almost empty. A little something adds security1,500kcals -(3 hours x 580kcals) = (-240kcals)
Need to supplement with at least 240 kcals for *optimal *performance (e.g. little to no power loss)Your situation is similar to #3. You took in approximately 200kcals during the ride. Which should have left you with basically nothing in the tank at the end of your ride, which is essentially what you experienced.

If glycogen stores were not completely full due to daily training; less storage = bonk more likely Some time spent above zone 2 = faster CHO oxidation = bonk more likelyTaking CHO in drink = bonk less likely

Disclaimers:

  1. Everyone is an individual, actual numbers will vary
  2. I didn’t necessarily do all the math, the numbers are close enough for illustration, but rounded for simplification

This is great. Thank you!

18

That is a nice theoretical analysis you’ve done. Maybe i’m always doing too much but, often times by Sat when i do my “long” ride, i’m usually pretty tired and go relatively slowly regardless of whether i take in any carbs or not. I don’t train by power but rather just speed and perceived effort (PE). MY PE is pretty low on these rides and i’m going pretty slowly but it is simply the best i can do given my fatigue from previous days training. Generally i’ll train pretty hard for 4 weeks or so, then take a very easy week and my body seems to bounce back stronger and faster, so i think my training is working. I don’t really have a question per se but just want to point out that analyses like the one you’ve done only work under certain semi-ideal conditions, basically where the person has not been doing a huge amount of training but has been doing enough to ride for 3 hrs.

19

First - I’m glad to hear that you feel you’re making gains and that your training is going well.
Second - It certainly sounds as though accumulate fatigue may be leading to a reduced workload during your longer effort. This can be independent of glycogen depletion or because of it. Hard to say without knowing more.

Ultimately strategies are neither good nor bad; what matters is whether they’re congruent with your goals.

I don’t really have a question per se but just want to point out that analyses like the one you’ve done only work under certain semi-ideal conditions, basically where the person has not been doing a huge amount of training but has been doing enough to ride for 3 hrs.

Unsure of what you’re saying here, so I’ll answer what I believe you’re suggesting.

What I think you’re saying: This falls apart when someone has prior training, carbohydrate depletion and fatigue.

Napkin calculations such as I did are 1. very easy to do and 2. helpful in exploring reasons for reduced performance. Because the original ask was “I bonked, but do not understand how that’s possible”, my goal was to logically show that it wasn’t just a possibility, but the likely outcome given the situation.

While I’ll agree that arm-chair quarterbacking across the internet leaves a significant number of variables undisclosed, making it more difficult to be extremely accurate, it’s fairly easy to know the status of athletes that you work with over time. In addition to non-invasive methods of assessing CHO storage, you can utilize diet logs to monitor intake while calculating caloric expenditures. Laboratory testing and the knowledge + experience to appropriately analyze it all makes life a bit easier.

Furthermore, The window of success is pretty large:

  1. Take in enough calories to avoid bonking
  2. Avoid taking in so many calories that you cause GI distress or carry excessive weight.
20

First - I’m glad to hear that you feel you’re making gains and that your training is going well.
Second - It certainly sounds as though accumulate fatigue may be leading to a reduced workload during your longer effort. This can be independent of glycogen depletion or because of it. Hard to say without knowing more.
Ultimately strategies are neither good nor bad; what matters is whether they’re congruent with your goals.

I don’t really have a question per se but just want to point out that analyses like the one you’ve done only work under certain semi-ideal conditions, basically where the person has not been doing a huge amount of training but has been doing enough to ride for 3 hrs.

Unsure of what you’re saying here, so I’ll answer what I believe you’re suggesting.

What I think you’re saying: This falls apart when someone has prior training, carbohydrate depletion and fatigue.

Napkin calculations such as I did are 1. very easy to do and 2. helpful in exploring reasons for reduced performance. Because the original ask was “I bonked, but do not understand how that’s possible”, my goal was to logically show that it wasn’t just a possibility, but the likely outcome given the situation.
While I’ll agree that arm-chair quarterbacking across the internet leaves a significant number of variables undisclosed, making it more difficult to be extremely accurate, it’s fairly easy to know the status of athletes that you work with over time. In addition to non-invasive methods of assessing CHO storage, you can utilize diet logs to monitor intake while calculating caloric expenditures. Laboratory testing and the knowledge + experience to appropriately analyze it all makes life a bit easier.

Furthermore, The window of success is pretty large:

  1. Take in enough calories to avoid bonking
  2. Avoid taking in so many calories that you cause GI distress or carry excessive weight.

Hello Robert - Thanks for responding. You did indeed correctly interpret what i was trying to say. I understand that you were just trying to show the OP that his bonking was not at all out of the norm. I was not meaning to seem critical but rather to point out that taking in carbs is not always going to make you able to sustain your goal pace, since once you’re past a certain point in fatigue, it’s all downhill from there and you just have to go at whatever pace you can manage. Anyway, thanks again for responding. Your posts are always insightful. :slight_smile: