Nutrition Rules of Thumb

So I am reading thru the Forum, yes I’m a new user here. I’ve been riding on a WAHOO KICKR for a few years and riding outside for more than a few years. I have never really focused on nutrition other than the en vogue gels while riding outside. I recently watched a TrainerRoad Youtube video where they discussed the benefits of Green Tea. This got me really thinking about my nutrition habits. I recently lost 40+ lbs using a KETO like diet and was planning to continue until I lost 20 or so more pounds . I will admit I let myself go and was way too heavy to be riding, my spokes were telling me after a few hundred mile. But I am getting back to the basics now. Since the KETO thing I noticed 45 min on the trainer and I am wiped out. I realize this is because of my current diet. What I am trying to do now is locate some general rules of thumb for cycling nutrition. I saw some one post in another thread about an 80/20 rule. I am not sure what that is or if it is even applicable. I have been reading the forum, but it is like drinking from a fire hose due to all the information posted. Is it OK to keep a KETO lifestyle off the bike and consume carbs and sugar while on the bike/trainer? If so, what do you recommend? Any advice is appreciated.


Keto only works if you do it 100% of the time. Otherwise you’re just keeping yourself in a perpetually glycogen-depleted state and setting yourself up to bonk almost immediately every time you exercise, as you’ve discovered. That being said, being fat-adapted is something of a spectrum. I don’t do keto at all, but I’ve gotten to where I can do a 120mi z2 ride totally fasted without bonking. At higher intensities your body will start to burn a much higher % of glycogen:fat, though, so for intense sessions you’re going to need carbs unless you fully commit to keto. Even then, most of the literature I’ve seen suggests that you’ll never quite reach optimal performance while on keto.

Golden Rule of Nutrition: calories in vs calories out is all that matters for weight loss. Even on a true Keto diet you only lose weight if you’re in a caloric deficit. Keto just tends to make it easier to do this because it’s fat that makes us feel full, while carbs tend to make us want more carbs.


General rule of thumb is fuel for your workouts. Higher intensity requires carbs period. Even as a keto athlete you will have some glycogen on board to supply some of your carb requirements, but if performance and gains on threshold and above efforts is a main goal you need to eat carbs beforehand to keep your glycogen stores high. If losing weight and lower intensity riding is your main goal then you can get away with some fasted/keto/low glycogen rides after some adaption period


Nutrition rules of thumb:

  1. Avoid processed and ready-made food. Cook from scratch, using fresh, local ingredients.
  2. Eat in tune with your body. Find out whats good for you and what isn’t. Everyone is different, some people can go high carb, some do better on high fat.
  3. Don’t stress it. If you feel good, have energy, and an appropriate weight for your size, you’re likely not far off doing it right.

Thank you. Very helpful info. I am trying to make a decision on how I will go from here. One of those options was to depart the KETO lifestyle. I’ll have to revisit my training goals and make a decision from there. I may have to lower my intensity…

+1 on everything here, especially the “Cook from scratch, using fresh, local ingredients”.

I would also recommend “The Endurance Diet” by Matt Fitzgerald - it’s obviously not KETO as it’s carb centered, but there is a ton of useful advice there.


Ditto. I’m HFLC —> Keto for the past ~3 months and can do 5 hr Z2 rides on just water (12hr fasted). Around the 2-3hr mark I do get “hungry”, but that passes within 10 minutes.

Medical reasons keep me from doing high intensity work at the moment so I’m taking this opportunity to focus on fat adaption via low intensity work as well as really dialling in a sustainable healthy diet.

But agreed, unless you are 100% fully fat adapted — which can take a couple of years — you’ll need carbs for higher intensities. FA just allows you to work at higher low intensities using fat instead of carbs, but eventually you’ll require carbs.

Also agree that Keto isn’t a fat free for all. Weight loss is calories out > calories in — no matter the source of calories.


Not sure if this is exactly what you are asking but this is always the article I come back to when trying to eat healthier and/or lose weight:

I like the incremental approach of going after the lowest-hanging fruit first.


This was very useful. I am really close to this method. I just need to make a few adjustments, abandon the KETO lifestyle, and make adjustments to pre-workout caloric intake. With these I should be able to maintain my lifestyle and achieve my goals.

Thank you for the advice

Just read this book and do what he says. 5 easy to abide rules, and more detail if you want to go there. Do that stuff, and fuel your rides. Your performance will thank you.


I also follow The Endurance Diet. It’s an easy way to stay in track without getting OCD about your eating.

+1 for that book. There’s also an iphone app which just lets you track the Quality of what you eat, not the quantity.
It quickly shows you whether you are actually putting in “good” stuff or “crap stuff”.

Interested to know how you’re feeling at the end of this. I’m not adapted and could probably do the same, but doubt I’d be good for much.

I love the app. Not using it right now as I have less control over what I’m able to eat, but it’s a useful tool. As someone said above, it lets you monitor your diet without going OCD. So long as you’re eating mindfully and eating quality foods, alongside your training/exercise, you’re going to come close to optimizing your weight and performance, IMO.

I went keto before the current rage on keto (I wasn’t competing in endurance sports at the time), and I was just a miserable person to be around for several months. Once I was fat adapted, I found that I was hungry more frequently than when I’m eating balanced. I didn’t care for it, and didn’t notice any kind of health or performance benefits (I was already lean), so I’m back to being a proud sugar burner.

Can somebody clue me into the scientific basis behind this? Why is fresh local corn on the cob better than the same amount of corn that’s been canned from another state? Does the nutritional value of it change when in a can, and what’s the time dependency of that? Again, looking for scientific papers, not a blog or website that just says it’s better as I’ve googled plenty of those…

Some good primer videos on nutrition (though they aren’t super cycling specific)

Generally speaking local food was ‘vine ripened’. That is to say - it didn’t need to be harvested long before it was ripe and then shipped halfway around the world.

The biggest difference this will make is in taste if you’re looking at fresh produce. For instance, in the north eastern US, strawberries in early summer are cheap and delicious because they are grown within driving distance of your grocery store. In the fall or winter strawberries are more expensive and don’t taste quite so good since they’re coming from (usually anyway) somewhere in the southern hemisphere

This is also why we see peaches in abundance in July/August but they typically aren’t even sold the rest of the year because they can’t be picked and shipped.

As for specific health differences between these two approaches - I’m not sure. I stick to local or regional things when possible, and where there’s the biggest bang for your flavor buck. Bananas are available year round for me but are never local, and honestly I can’t tell the difference between in and out of season. Other things it is more important - blueberries for instance I buy in large quantities all summer (they are cheaper and taste better) but I don’t touch them in the fall or winter. Same for tomatoes - I love a fresh local tomato and will eat tomatoes like an apple at this time of year but the ones we get in the winter that are white inside aren’t edible in my opinion.

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I don’t think there is a scientific papers on that as you wouldn’t compare apples to apples.
I think the rationale is that in theory there shouldn’t be a difference, but in practice when the corn is getting put in the can, it’s not only the corn - it’s being added a ton of other products, not very healthy.

Another example (not perfect though) may be orange juice - while oranges are very good and healthy, orange juice is much easier to ‘overdose’ to the point it becomes unhealthy. In theory orange and orange juice is almost the same, yet it’s not.

Also, a data point N=1 - here is my weight from the last 2 years:

  • black lines - periods when I eat everything, including processed food and quite a lot of alcohol. Overall I eat a lot of veggies, but also some processed food and certainly a lot of sugars / candies too and snacks to go with alcohol

  • red line - Ironman training - where I trained around 10-15 hours per week


  • you can see that my weight correlates very little with my training regime
  • beginning 2018, I eat very well - only stuff cooked by myself. I didn’t follow the ‘Endurance Diet’ per se, as I didn’t knew the book at the time, but it matches very well how I eat
  • notice the period towards the end of Ironman preparations - same thing - to drop before the race, I started to eat clean again - only home made food
  • after the Ironman - the last black line. Well, I deserve a little break :slight_smile:

Anyway, it’s just N=1 (well, N=2, as it’s the same for my partner), but for me it’s just that simple - I eat what I prepare myself => weight going down drastically. I eat processed food (+ alcohol) => weight going up and it’s completely independent of how much I train.

I’ve been HFLC for many years and with the workouts on TR there’s no way i could complete on KETO. I can pretty much complete any workout fasted. As Chad states in his workout commentary plan out your post ride nutrition. add back the carbs you’ve depleted with quality food-based carbs, not sweetened drinks.