Fat-Loading for Race Performance (part 3)

sarah cuff Ergogenic Aids 36 Comments

There are many ergogenic aides available to runners to help them achieve optimal performance on race day. For those participating in endurance events lasting longer than 2 hours, one such technique you may wish to try is fat-loading.

The purpose of fat-loading is to teach the body to burn its own fatty acids as fuel (to a greater extent than it already does), thereby conserving glycogen stores. Conserving glycogen stores as much as possible will help to prevent ‘bonking’ or ‘hitting the wall’ on race day. Fat-loading also tends to help runners reach their desired racing weight on race day, a benefit I personally was very pleased with when I tried fat-loading for the first time last July.

I wrote in part 1 on WHY you might want to try fat-loading, including stories of those who’ve tried it. Then in part 2 I detailed what the science has to say on fat-loading. Finally, here in part 3, I’ll take you through exactly HOW to fat-load properly.

First, allow me to outline the ground-rules, disclaimers and reminders:

  1. Fat-Loading is appropriate for those racing events such as the marathon, ultra marathon, Ironman triathlon and GranFondo (basically, any race that is over 2 hours in length).
  2. Begin fat-loading 13 days out from race day (meaning fat-loading will begin on a Monday if your race is on a Sunday).
  3. Fat-load for 10 days (Monday through to Wednesday of the following week); then carb-load for final 3 days (Thursday, Friday, Saturday). It is very important to follow the 10 day fat-load with a 3-day carb-loading period to ensure you have full glycogen stores to draw on for your race.
  4. On race day (Sunday), execute your high-carb race day plan as per practiced.
  5. Fat-loading is not appropriate for everyone. It is typically a large deviance from the runners normal nutritional practices and in cases where the athlete is not used to the amounts and/or types of fats that must be eaten in large quantities, may cause digestive upset.
  6. A diet low in carbohydrates (low-carb is a default of fat-loading) can cause feelings of fatigue, lethargy and malaise. If you are fat-loading and experience feelings of dizziness, fogginess or lightheadedness – eat a piece of fruit or have some fruit juice immediately.
  7. Note that the list of healthy high-fat foods that may at first sound appealing, can get monotonous and tiring very quickly. Be prepared for little variety over the course of ten days.
  8. Lastly, although I’ve personally tried fat-loading for the first time before an important race with great success (and have had numerous clients do so also), I caution against doing anything for the first time without acknowledging that it may not work for you. If your upcoming race is key and very important to you, it may not be the right time to experiment with fat-loading.

And now, on to what to eat!!

Consume roughly 65% of your calories in the form of fat, with the remaining 35% split between protein and carbohydrates.

Foods to eat

  • All nuts (such as almonds, pecans, walnuts, cashews, peanuts, Brazil nuts, pine nuts) – raw or dry-roasted preferably with sea salt
  • Pure natural nothing added nut butters
  • Nut ‘cheeses’ such as cashew cheese
  • All seeds (such as hemp hearts, chia seeds, sunflower seeds, sesame seeds, pumpkin seeds)
  • Pure natural seed butters such as tahini and Sunbutter
  • Full fat organic tofu
  • Virgin coconut oil and extra-virgin olive oil
  • Avocado (aim for ½ to 1 avocado per day of fat-loading)
  • Olives
  • Coconut butter / coconut mana
  • Unsweetened coconut chips or shredded coconut
  • Coconut butter and cacao butter
  • 85% dark chocolate
  • Full fat coconut milk
  • Organic, free-range eggs
  • Wild fatty fish (salmon, halibut, mackerel, sardines, herring)
  • All veggies and lots of leafy greens (no yams or potatoes)
  • Moderate amounts of organic, grass-fed, pasture-raised lean proteins
  • Berries

Drink lots of water – add lemon/lime/berries to the water to add taste if desired. Also drink tea and matcha and other hot beverages with almond milk (or organic cream). And if you like kombucha, you might have one low-sugar (~5g carbs/serving) kombucha daily (such as GT’s Gingerade).

If you are certain you do not have a dairy-intolerance, you may wish to include the following:

  • Organic grass-fed butter
  • Organic grass-fed full fat hard cheese (preferably raw, unpasteurized)
  • Organic grass-fed full fat greek yogurt (plain, nothing added – must be full fat)
  • Organic grass-fed full fat heavy cream

Foods to avoid / greatly limit

  • Concentrated sources of carbohydrates such as sugar, grains (rice, oats, quinoa, buckwheat, millet, etc), legumes (chickpeas, beans, lentils), fruits (berries are okay)
  • Sugar (avoid all sugar including natural sugars)
  • Low-fat dairy
  • Soy milk, rice milk
  • Large amounts of concentrated protein (meats) – no more than 2-3 oz at one meal, 2x per day
  • Alcohol
  • Juices of any type

So how would you go about putting together a menu using these lists? Below you’ll find 4 examples of a day in the life of a fat-loader:

Example #1 (vegan):

  • Breakfast – Breakfast smoothie with spinach, ½ an avocado berries, almond or coconut milk, coconut oil, coconut or almond butter, and organic protein powder
  • Snack – Mix of nuts, seeds, coconut chips/flakes (optional few pieces 85% dark chocolate)
  • Lunch – Kale salad with sautéed tofu, hemp hearts, walnuts, veggies and an olive oil / lemon juice dressing
  • Snack – Cashew cheese and celery with olives
  • Dinner – Tofu and veggie scramble sautéed in coconut oil or butter with avocado

Example #2 (vegetarian):

  • Breakfast – Bowl of chia pudding (or full-fat greek yogurt) topped with fresh strawberries
  • Snack – Mix of nuts, seeds, coconut chips/flakes (optional few pieces 85% dark chocolate)
  • Lunch – Kale salad with a boiled egg, avocado, pecans, hemp hearts and an olive oil / lemon juice dressing
  • Snack – Bowl of blueberries drizzled with generous amount of almond butter mixed with water (to thin enough for pouring consistency)
  • Dinner – Egg frittata served with avocado and salsa

Example #3 (pescatarian):

  • Breakfast – 2-3-egg omelet with veggies and avocado (optional cheese)
  • Snack – Mix of nuts, seeds, coconut chips/flakes (optional few pieces 85% dark chocolate)
  • Lunch – Halibut baked with olives and tomatoes with side of sautéed kale (sautéed in coconut oil) with sesame seeds
  • Snack – Small bowl of chia pudding (chia + coconut water) or full-fat greek yogurt (no sugar) topped with hemp hearts and fresh strawberries
  • Dinner – barbequed salmon with side of sautéed asparagus (in coconut oil or butter) and a miso-ginger-coconut sauce (using full-fat coconut milk)

Example #4 (meat-eater):

  • Breakfast – 1 organic, grass-fed bison sausage scrambled in grass-fed butter with onion, bell peppers and spinach sautéed, served with salsa and ½ sliced avocado (optional organic grated hard cheese melted over)
  • Snack – Mix of nuts, seeds, coconut chips/flakes (optional few pieces 85% dark chocolate)
  • Lunch – Cream of chicken soup with lots of veggies (make with either coconut cream or organic grass-fed cream)
  • Snack – Celery with almond butter and olives
  • Dinner option 1 – 3 ounces of baked or barbecued organic chicken breast over a salad of mixed greens, carrots, cucumber and tomatoes with pumpkin seeds, walnuts and half an avocado – with a dressing of olive oil, tahini and lemon juice
  • Dinner option 2 – BBQ’d grass-fed pasture raised steak with side of sautéed asparagus and red peppers (in coconut oil or butter) over wilted spinach

If you have ever fat-loaded in the past (or are currently doing so!) and have additional meal and/or snack ideas to add to the above suggestion, please do so in the comments below. If you choose to try fat-loading for the first time, I wish you all the best as you determine whether or not this is an appropriate ergogenic aide to use in your personal racing strategy!

To deliciously healthy food and stronger faster running… Cheers,


Sarah Cuff, R.H.N.
Holistic Sports Nutritionist
Founder Eat 2 Run Sports Nutrition
CSNN Sports Nutrition Instructor
Better Bodies Club Nutritionist

Comments 36

  1. Pingback: Fat-Loading for Race Performance (part 1) | Eat 2 Run

  2. Pingback: Fat-Loading for Race Performance (part 2) | Eat 2 Run

  3. I’m curious what kind of running you did while fat loading. I’m trying this (day 4) and on day 3 ran 9 and the last few miles were tough. Normally I would try to get in a couple more runs of 8-10 in the next few days. But dont know if I should adjust this while fat loading.

    1. Post

      Hi Danielle… I followed my usual run schedule while fat loading – had one really tough workout 2 days into fat-loading, track workout, paces were slower than usual and felt way harder. Days 3-7 were hardest. But I would expect all that. It is still worth it to do all the workouts, I just wouldn’t expect to hit pace or have them actually feel that easy. It’s actually a good idea TO run while fat-loading, as your body is adapting and learning to use more fatty acids for fuel. Good luck!

  4. What brand of Greek yogurt to you use… So many brands out there? I’ve bee using Olympic plain Krema (approx.11% fat) or their regular plain (approx.3.5%) but wonder if it’s ideal!

    I’ve really enjoyed reading your Fat loading, carb loading articles since I’ve bee exploring low carb, high fat, & moderate protein eating plans. I’m also running the BMO marathon on May3 and will definitely consider applying your carb loading strategies! Thanks for all the useful information! Nice to have an expert who is local!

    1. Post

      Hi Gisele… I don’t usually eat yogurt, but bought a grass-fed yogurt this week to try that is make by “The Farm House”, purchased at Whole Foods. I was happy to see how many grass fed options they had. It has 7 grams fat per 1/2 cup serving, and I’d say that’s about as low in fat as you’d want to go. I was hoping for higher. Your 11% fat one sounds pretty good! And awesome, glad you’ve been enjoying the articles! I’d love to know how it goes for you and how your BMO marathon goes – good luck!!

      1. Thanks for the quick response and the 7% or higher fat suggestion. Knowing of more places where one can purchase more grass feed products is great also!
        I’ll be in touch after the Marathon ( my 2nd…1st one in 2000!)!
        I look forward to hearing how you do, especially with the fat & carb loading! All the best to you in the next weeks and marathon!

        1. Post
  5. Hi Sarah,
    I enjoy your site a learning a lot from it, Thank you!
    I’ve decide to try fat loading during practice to ensure I can make it during the real thing. During massive training I usually take GU gel every ~45 min. What are you suggesting to eat or drink during the training in the fat loading days?

    Thank you,

    1. Post

      Hi Lizou… So great to hear you find the info here useful 🙂
      About the fat-loading… The great thing about doing it while tapering for a race is that during taper the workouts are less intense, therefore not fueling as usual isn’t such a big deal. If you were to try fat-loadng during your regular training, you’re either going to sacrifice performance for lack of carbs being taken in, or take a short diversion from the fat-loading and fuel as usual with gels in order to get a strong workout in. During training I’d suggest the latter. Use your usual gels, but maybe also throw BCAAs into the mix.

      Good luck, let me know how things go!

  6. Pingback: How to Avoid the “Runners Trots” | Eat 2 Run

  7. Hi Sarah, your articles are fantastic and Devon’s recent blog about Fat vs Carb is what peaked my interest. I’m training for an upcoming 50-mile endurance run and realize it is too close to race day to get in the 10day/3day fat-carb combo. I’ve followed your 5 day cleanses in the past and make the both gel recipes that are super yummy and I have noticed a difference in my energy levels. Just wondering if the 10/3 can be shortened a little… My race is Oct 10th…

    1. Post

      Thanks so much Pam, so great to hear you enjoy them! For sure, even a 5-day fat-load + 1-day carb-load has been shown to enhance the bodies ability to burn fatty acids for fuel while racing, so if your race is October 10th, I’d recommend either fat-loading tomorrow (Sept 30th) through to Oct 7th (8 day fat-load) + a 2-day carb load (Oct 8th and 9th); or a 7-day fat-load (Sept 30th to Oct 6th) with a 3-day carb-load (Oct 7th to 9th). The shorter the carb-load the more accurate you’ll want to be with it. Either of these versions should provide you similar results! Good luck!

  8. Sarah I wanted to let you know how my race results went. Even with the shortened time frame, (I did 8day/2day combo) it worked! I was nervous because the days leading up to the race I still struggled and felt sluggish. But by the time I reached day #8 and then went on to 2 carb days, I felt great. I finished my 50-miler! It was a difficult course with a 13-hour cutoff. I barely dented the chocolate mint ge supply I made considering my finish time was 12:44. No bonk, no multiple stopping for the call of nature. Although my training was sporadic because of work I am amazed at the results. Your recipes are great and I am happy I stumbled on your website. Thank you!
    -Pam ~_~

    1. Post

      Wow Pam – I can’t believe I missed your comment here – but WOW this is so awesome how well fat-loading worked for you – not surprised but super happy to hear it 🙂 Belated congrats to you!!

  9. Thank you for this great series on fat loading! Matt’s book “New Rules” is basically my training/eating bible. I finally tried fat loading last week in preparation for a July 4th Half. Your site was so helpful in guiding me for plant-based fat loading. Unfortunately I contracted food poisoning during my final pre-race day and wasn’t able to run my half yesterday. I registered for another half this coming Saturday. I don’t think I’ll have the time or GI tolerance for another fat load, unfortunately. I’ll definitely still carb load per usual. Any tips for salvaging training or fueling over the next few days?

    Again, thank you so much for compiling this information. Especially for a non-omnivore, it was incredibly helpful!

    1. Post

      Hi Megan… Apologies for missing this comment! I hope you had a great half marathon? So sorry to hear you got food poisoning on the last day before you were to run your fat-loaded half, how unfortunate 🙁 I hope you’ll have another opportunity to give it ago soon – and would be interested to hear how it goes for you! All the best, Sarah

  10. Hi, I enjoyed reading your article but didnt find info on how to do the carb load the three days before. Wondering what kind of carbs, how many and does this mean we drop the fat and protein percentages way down? Thanks for your help

    1. Post
  11. Back in early Feb, I attempted to BQ at Surf City and bonked very early- by mile 10 I could tell my energy was draining and no matter how much fuel I was putting in, I could not get my energy back. Thanks to a friend who helped me through the last 6 miles, I finished respectably but didn’t get my BQ. I was running LA six weeks later with my team, but knew that was too soon to try again for a BQ, so I just enjoyed the race. But I also figured it would be a good time to experiment with something new because clearly nutrition must have played some role in my issues at SC. So I tried fat loading. Admittedly, I didn’t carb load properly after the fat loading- it was my 10th anniversary so 2 days before the marathon I was wine tasting and eating cupcakes. BUT, I still ran a very comfortable LA, finishing a minute faster than SC without even really trying. Flash forward about 5 weeks, and in a spur of the moment decision I decided to sign up for Mountains 2 Beach at the end of May- just 5 weeks out. I had not trained. But I had maintained a decent level of fitness after LA. I knew I had time to get one 16 miler and one 20 miler in before taper, plus a few long tempos. Not really the BQ training I would have liked, but that’s where I was. This time, I went all out with the fat load/carb load phase- held myself to a strict standard for fat loading, and ate only the good carbs during the carb load days (loved the power cookies, banana bread and choco beet muffins, btw!). My previous marathon PR- 3:51 and change. Yesterday’s race….3:40:39. BQ by 4 minutes 21 seconds. I felt amazing through mile 21. And even when I started to decline, I knew I still had the energy to get through to the finish without bonking hard. Now I am curious to know what would happen if I trained hard AND had my nutrition game going strong. But I think I’ll take a little rest for a bit. 😉 Thanks for the fabulous info on your site! I am sharing it far and wide!

    1. Post

      This is just amazing Peggy, thank you so much for sharing your story here!! Huge congrats on your BQ – woohoo, so happy for you! That is so interesting how you did notice some positive benefits by kind of following the protocol the first time around, but then by putting it all together you really noticed the difference – it really is about both fat-loading and carb-loading properly – what a great example of this!! And yes, all that without hard training – amazing. Definitely take your much deserved break, rest up and enjoy your down time… And when you jump in again with both training and nutrition going strong, I’d love to hear about the outcome of that 🙂 Congrats again!!

  12. I run on the same marathon charity team as Peggy Kennedy, who commented above, for the last 5 years so we have shared a lot of our marathon stories. She told some of us about this after her Boston BQ and I figured I would give it a try for the LA Marathon this past sunday. While I have managed to chop time off of each marathon (4:37, 4:24, 4:14) one thing remained the same, my quads stinging and aching and overall legs just feeling like they are no longer firing like they should be around mile 20-22. I managed to run through that discomfort last year but it was still there. Dead legs I guess. I did the fat loading for 9 days. . . 10th day i started to transition to half fat loading diet, half carb loading. I admit to having a sugar addiction even though my meals are really healthy, and my stomach by day 9 felt really raw and gross. I literally had no appetite even for things I love like fish that I never get to eat because my husband doesn’t eat it. Not to be too graphic but had some loose bowel issues and got scared so I transitioned on that last day. I don’t know if there is any truth to what my sports masseuse suggested, but he happened to ask me if I had diarrhea on the fat loading diet and I was like “funny you say that” LOL. Anyway, he said sometimes those diets can help reset your gut bacteria and it’s your body getting rid of bad sugar hungry bacteria. Not sure if there is any truth to that, but curious to know what you think. ANY WHO, the great news is, I had a goal of 4 hours. Stayed with my pacer and had a few moments questioning if I could sustain that tempo, but I did! I had unrelated foot pain, just balls of my feet on fire, but honestly that’s all I struggled with! I never once felt like my legs were dead and felt that I still had gas in the tank all the way to the end and came in at 3:58! I honestly could NOT believe it. I do believe this might have really made the difference for me. Thank you!

    1. Post

      Hi Erin… Thanks so much for sharing your experience with fat-loading here!! And CONGRATS on your sub 4-hour marathon!!! That’s amazing, so awesome. I’m actually super impressed with how well your body tolerated fat-loading on your very first try. I’ve heard many, many stories of people who tried and had to stop, then try again later, or adjust diet previous to fat-loading, in order to avoid the exact issue you dealt with – digestive upset. I don’t know how much fat you ate previously, but let’s say you’re average, which is about 30-35%, and then to fat-load you jump to 65-70%. Your body needs to adapt (by creating more specific enzymes that help to breakdown the fat), but with fat-loading we don’t really give the body time to adapt – so it responds by not being able to fully digest all the fatty foods. It also depends on what type of fatty foods you chose. There’s a lot of choice… And some forms of fat are better for your system than other forms – for example all processed cooking oils (canola oil, corn oil, soy oil, sunflower oil, safflower oil, etc) can make one feel quite ill after ingesting high amounts for even just a few days. Of course, despite these issues, fat-loading still works its magic, just as you experienced! Typically with clients, I ideally have them consuming a 40-50% fat diet before jumping to fat-loading (which is not always possible). Regardless I do notice, no matter the usual fat intake, the more often one returns to fat-loading (say, practicing it multiple times per year before each race), the better it is each time. Thanks again for sharing your story – and congrats again!!

      1. Interesting. I will have to try that next time. My husband is vegetarian so I don’t tend to eat a lot of meat but we do eat lots of rice, grains, beans, and veggies in our typical diet. The smell of coconut oil in the pan made me nauseated by day 7-8. I actually cut out dairy the first half just because I felt like it. I was using coconut oil in my coffee in a bullet blender which I do anyway sometimes instead of half and half. I was mostly eating chia seed pudding with berries, coconut shavings, hemp seeds, walnuts, almonds, sugar free nut butter, salads with tofu or chicken or steak. Salmon halibut and eggs with veggies. At least a half an avocado a day and some 85% dark chocolate. I would do it again since it worked though. My runs on that diet were interesting. If I was moving I felt fine. If I stopped at I light I got nauseous and suddenly couldn’t catch my breath but it would go away the second I started running again. By my last long run (10 miles day6 of the diet) it wasn’t as bad but still there.

  13. Hi Sarah
    Couple of questions:
    limit/avoid soya milk? but tofu is ok….why’s this?
    limit/avoid sugar, but a little dark chocolate is fine? (I’m thinking that dark chocolate has sugar)
    Love your site!
    Thanks Jacqueline

    1. Post

      Good questions! Basically, you’re looking to consume foods that are high in fat and simultaneously low in carbs. Therefore, while full fat tofu makes sense (3g carb and 4g fat per 85g serving), most soy milk doesn’t (9g carb and 4g fat per cup). Dark chocolate you must simply ensure the nutrient data is acceptable – it should have approx double the fat than carbs – my 90% bar contains 6g carb and 11g fat per 20g serving. Cheers, Sarah

      1. Hello Sarah
        That makes sense. I think I’m ok with the soya milk; the one I use has 1.9g fat and nil carbs per 100ml.
        I tried adding a few raw cocao nibs to my coconut milk yogurt as they were super tasty and high in fat 55g and low in carbs 6g per 100g.
        Thanks for your advice.

  14. Hi Sarah, I met you at a Canfit conference in Vancouver where you were presenting and have followed you since. I am currently preparing for my first Ultra (50k) Trail Race and have just started your 10 day fat load. For a long run I would normally put BCAA in my water for during the run and for after I would have either my whey protein shake or your Chocolate Cherry Berry Recovery Shake. Can I still utilize these? (I tend to go heavy on the protein since I am in my 60’s.)
    Also, although I love coffee, it tends to give me runners trots. I’d love to have an alternative for race day that won’t cause issues. Suggestions?

    1. Post

      How exciting you’re preparing for your first ultra! Great questions… putting BCAA in your water during your run is okay – but in theory what you’re doing is providing the body with amino acids it might utilize for fuel during the run, whereas the point of fat-loading is to push your body into burning fatty acids for fuel. Personally I’d avoid BCAA’s during fat loading. Afterwards, that’s awesome you normally have a great recovery smoothie, which is so necessary. However for the purpose of fat loading, technically you’d want a shake with protein and fat – so you could do coconut milk and protein powder and avocado and cacao and hemp hearts, etc… But not the usual banana or tart cherry juice. All that said, if you’re going to include some carbs during this time, immediately post long run is THE time to do it!! And I’d try matcha pre-race instead of coffee (experiment first of course). Good luck! -Sarah

      1. Thanks Sarah! I will try those suggestions. Tomorrow is my first long run while fat loading so I’ll see how it goes.

      2. Hi again Sarah,
        So I did my 30k ski area race and did much better than expected. I didn’t get the 10 day fat loading in (good friends, good wine ….), but I did get 4 days in then 2 days of carb-loading. Even with that I was able to go longer before needing fuel and cut off about 25 mins from my 28k race 5 weeks before. So thank you!!
        I am currently on day 3 of my second attempt at fat loading before the 3 day carb load for a 40k a week Friday and hope to stick to it.
        One question though … while you are doing the 10 day fat load, what do you use for nutrition on a long run? eg. 25k?

        1. Post

          That is amazing Fay, congrats!! And it does make sense in a way, as we do know a 5 day fat load plus one day carb load works, so your version was very close to that!! Great race result, awesome stuff – thank you for sharing.

          And you’re at it again! So for long runs during fat loading, I do them with just water. That said I’ve never gone longer than 26 km while fat-loading. And I always bring a gel just in case. But doing longer runs without fuel like that is actually a form of training that some elite marathoners use in prep for race day (possibly an older practice now though), as it does teach the body to reach for fat-stores for fuel – as rough as it can feel while out there, it does help with adaptations. Also, the more often you do it the easier it gets – I’ve had clients who’ve come to me thinking it was normal to run 25 km with zero fuel simply because that’s just what they’ve always done!!

  15. Hi, Sarah. First of all thanks for the 3 part article you published on this particular subject of loading prior to a race. I’m a 57 year old male who is currently training for spring runs of 5 & 10Ks with aspirations of running in his first Half in September. I’ve been running for over 3 years now but a recent knee injury took me out of the loop for 6 months. I’m back to running distances over 5 miles and have done so on a rather strict Keto diet and feeling great. Sorry for all the background but I guess ultimately my question is when prepping for a long race on a Keto diet should I chance the 3 day Carb load period or should I just go with 10 day fat load? I don’t know that I gleaned that theory from the articles. After an 8 month running season, I’m planning on a 2 month break from running after the Labor Day race. Any information will be gratefully appreciated.

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