Sleep, damnit! How a bad night’s sleep impacts both eating keto and Ironman training

Sleepy runner girl

I missed swim workout this morning … and it’s 100% my fault.

I’m a light sleeper. A good night’s sleep makes everything easier. I can set myself up for a good night’s sleep starting around noon the day before – no caffeine, right food, light dinner, right hydration, stress reduction (meditation, yoga, stretching, foam rolling, breathing, journaling), good sleep habits.

Conversely, I can throw tomorrow’s workout out the window by doing things that cause me to have a poor night’s sleep.

As it turns out I can also really hamper tomorrow’s eating by sleeping poorly.

Let’s dissect this beast.


For me the countdown to a good night’s sleep starts at about noon the day before. That’s mainly because any caffeine and food intake after that point continue to have an impact on my body when I’m trying to get to sleep: I like to sleep 9pm-5am.

After many, many years of drinking too much coffee, I finally switched to decaf once I figured out that it takes my body a long time to metabolize caffeine. My wife can have a cup of coffee at 6pm and happily go to sleep at 9 or 10. not me. We’ve taken to occasionally walking to 7-11 for a Diet Coke – you know, the 20oz bottle – at 1pm-2pm for something sweet and I’m realizing that it’s destroying my sleep that night.

I find I even have problems with the caffeine from decaf if I have it in the afternoon.

This NIH study shows the half-life of caffeine in the body (the time to eliminate half of the dose) ranges from 1.5-9.5 hours. As they say, this is due to “innate individual variation”: everyone’s different!

So for me Rule #1 for good sleep habits is DECAF ONLY, ZERO CAFFEINE AFTER NOON! (I should probably back that up to 11am.)

As an aside, I loved caffeine as a focus drug. I miss the extra focus part but I don’t miss being addicted to something. As well, we buy great decaf so I still get good flavor and can still use that for bulletproof coffee in the mornings.


I have a sensitive system and eating the wrong foods – especially late in the day – impacts my sleep quality. This can be a range of things including:

  • GI distress, crazy dreams, and general discomfort
  • too much histamine results in breathing and snoring problems from being stuffed up, as well as itchy skin
  • extra soreness from too much inflammation
  • just the amount of food I eat at dinner can impact my sleep: discomfort from over-full belly, pressure on bladder means having to go pee more often
  • I gave up alcohol just over a year ago (I promise to talk about that in another post), but that caused significant sleeping problems as well.
  • eating late means waiting around to poop in the morning instead of things happening on the right schedule

All those things can combine to reduce sleep quality but they are not as well-defined as the caffeine cutoff limit. I do have some things I really try to get right though:

Rule #2 for good sleep habits: eat a light, early, keto dinner with the foods that agree with me.

I know that’s a little vague but part of your journey is to learn which foods agree with you and which ones do not. There are many ways to do this, including an elimination diet. I also suggest looking at what foods agree with your Ayurvedic Body Type (this was surprisingly accurate for me and has informed my journey over the years). You could also consider asking for an IgA (Immunoglobulin) test to see how your body’s immune system is responding to different foods.

Here are some examples of foods that are problematic for me:

  • foods heavy in garlic give me absolutely insane dreams
  • lightly cooked onions destroy me – burps, burning stomach
  • pecans give me an instant histamine response – stuffed up, throat scratchy
  • kidney beans … just no

As with caffeine intake, everyone is different! It takes time to sort out what your body is telling you but the faster you learn to hear what it’s telling you the happier you’ll be.


We talked about how caffeine and food intake can impact our sleep, but what’s the impact of getting a poor night’s sleep? Isn’t it just “ooh it was hard to get up with my alarm” or “dang it I missed my early workout”? As it turns out it’s quite a bit worse than that.

I was listening to a recent Joe Rogan podcast episode with Chris Kresser ( – well worth listening to) and was reminded of the hormonal response to sleep deprivation, mainly the impact of a bad night’s sleep on leptin and ghrelin levels. I had heard about it before but never really put it together with some of the problems I was having. They made a great point of not beating yourself up for getting sucked in by some of these snack foods: it’s a biological response in many cases.

Science to the rescue!

There’s this little gem of a study from the NIH – The impact of sleep deprivation on food desire in the human brain – that correlates sleep deprivation with increased calorie intake, increased intake of high-calorie foods, and changes in the parts of the brain that are known to be associated with those behaviors. I encourage you to read it: it’s quite science-y but you’ll get it.  There are many other similar studies related to leptin and ghrelin levels, your “hunger hormones”. In essence, the test subjects who were sleep-deprived ate more food and more high-calorie food in the period after the deprivation. I noticed this in myself after a bad night’s sleep compared to a good night’s sleep:

Good night’s sleep: awake with or before alarm, happily drink by bulletproof coffee and not hungry until late morning or even lunch, workout completed.

Bad night’s sleep (in this case because of a diet coke the day before): went back to sleep for an hour after alarm, missed morning swim, hungry as soon as I got up and continued eating all day! Not only that, more likely to have another diet coke the next day because I’m tired, perpetuating the cycle.


So what we have here are paths to success and failure both in training and in fat loss. Any coach will tell you that sleep is of the utmost importance because endurance training put extra stress on our bodies and we need time to heal. I want to add some things to that:

  • Having a poor night’s sleep makes it very unlikely that I will complete the prescribed workout the next day, certainly not with good quality. This has a cumulative effect on the week’s workouts and thus overall consistency.
  • Having a poor night’s sleep makes it likely that I will overeat the next day. Even if I overeat keto-friendly foods I will eat too many of them (nuts, peanut butter, cheese, etc.) to allow fat loss to occur. There’s a good chance I’ll put myself out of ketosis and have a similar cumulative effect on the week’s fat loss and overall consistency.
  • Those failures combine to make it more likely that I’ll fail in a similar fashion the next day because I’m tired and pissed off that I failed.

So, that’s me. Almost all my Ironman training and keto successes and failures are centered around getting a good night’s sleep, and I can associate those directly with my nutritional approach to the day before. What about you? Where does your body fall on the scale of metabolizing caffeine, light to heavy sleeper, sensitivity to foods? Let us know in the comments.

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