This is how I teach most my clients and athletes to dial in fueling, with an exception of a few with different needs. Only attempt diet and fueling changes at an appropriate time in your season (not before your big race), and if you are certain that you’re not suffering from ailments that could be worsened by changing your carb intake. Some examples of those who should avoid low carb: those with amenorrhea, clinical hypothyroidism, or severe adrenal fatigue, to name a few; and always consult with your coach or practitioner. Generally speaking, adopting a diet that allows for more metabolic flexibility and less reliance on carbs will be beneficial for health and performance, no matter your race goals. That said, some people tend to go overboard or get too OCD and a little too obsessed with the numbers and macro counts, so I address that here and it’s my goal for all of you to keep it a casual, healthy and intuitive approach to eating! And when all else fails, go by the 80-20 rule (see more in this article to avoid overly restricting). So whether your goal is to shed a few pounds or avoid the bonk, then read on!


Your Morning

Start this diet transition, if it’s new to you, when training loads are light such as in the offseason or pre-season. Do not make extreme changes to your diet if you’re in the midst of Ironman, marathon or ultra training—too risky; wait until after the race.

Your breakfast and/or pre-training fuel should consist of lower-carb higher-fat meals, i.e. avocado, eggs and veggies in coconut oil with berries breakfast. Breakfast should be 400-700 calories (not low cal!), based on your weight and activity level. If you workout very early and can’t have breakfast first, have at least have 50-200 calories of a snack such as coconut butter, nuts and a few berries or sugar-free full-fat yogurt with coconut flakes. Still eat breakfast after.

Don’t skip your morning fuel!

Starting your day with a fast (i.e. skipping breakfast completely) and doing a bunch of fasted morning training is not not going to be the ticket to success, health or performance. Keep fasted workouts to no more than one to two times a week. It’s a myth that fasted training is the only/best way to get fat-adapted. Even if you’re not hungry at 4:30 a.m. before masters swim or your group run, try to get a little something down before or during the workout session (try something like UCAN drink mix or their bars). Your body will thank you in the long run.

That said, if you’re truly repulsed by all food and drinks that early or maybe even still a bit full from last night, then you can skip your pre-workout calories but try not to make this a daily regular habit. It can and will bite you in the butt down the road (I’ve been there; I know) and you won’t excel in your fitness goals also adding to frustration and burnout.

Are pre-workout carbs ever ok?

Absolutely! Even the most fat-adapted will need some carbs especially when training volume and/or intensity are high. You don’t always have to train low (i.e. only have carbs post workout) either. Choose carbs that will digest easily and not cause bloating or gas; in other words choose low/non-FODMAP foods before exercise. I like the following:

My rule of thumb is once you’re fat-adapted and you know you can get by without needing carbs on a 1- to 2-hour aerobic workout (e.g. MAF run or bike), then you have achieved metabolic flexibility and can certainly add clean carbs in moderation before morning sessions.

But, you don’t need to overdo it on carbs or sugar, and certainly avoid the traditional mindset that athletes needs bagels and Kellogs cereal to fuel training—that’s where you could get in trouble long-term.

So how much pre-workout? Measure out 15-30 grams of carbs or so, give or take, and this should suffice for most people. Some people do not have a good concept of carb amounts and portions, and for this I recommend a food scale to get idea of how many grams of carbs are in your sweet potato, for example—I’ve seen clients shocked at how much they were actually eating in reality when they thought they were in eating half that amount of carbs. That said, the food scale is a tool not meant to become an OCD addiction; not every morsel you eat needs to be measured. Learn from it and move on from it. Here’s the food scale we have.

  • Some morning carb examples my athletes and I love include:
    • mashed sweet potato with melted coconut oil or butter;
    • gluten-free tortilla filled with nut butter, fruit, a drizzle of maple syrup (or honey if tolerated) cinnamon and sea salt;
    • real sourdough bread toasted with grassfed butter and an egg;
    • my grain-free porridge;
    • UCAN porridge;
    • roasted kabocha squash;
    • more ideas here and here.


Post-Workout & Evening Meals

Eat some carbs post-workout and again in the evening at dinner. For post-workout: You may need 25-75 grams of carbs (100-300 calories from carbs) with quality protein, amounts depending on if it’s a meal or snack; the longer you went the more room you have to add more. For protein, no more than 30-45 grams of protein per feeding is necessary. You can have up to 1 gram of protein per pound of bodyweight per day, not over that, and if you do the math you might see that you will need to supplement protein between meals to get in enough each day. Certainly always take a high-quality amino acid like BodyHealth’s PerfectAmino in pill or powder form.

Carbs in the evening help reload glycogen stores after a day of fat burning, and will help you keep from getting too depleted and also come back to help during tomorrow morning’s early workout! They will also help you sleep soundly and not toss and turn—obviously key to your success is quality sleep. Starchy root vegetables, squash, fruit, white rice, quinoa, and the like are usually good go-to’s.

It goes without saying, but always include some healthy fats with meals and snacks. For cooking oils or dressings: a combo of monounsaturated fats like olive oil and avocado oil along with saturated fats like coconut oil, butter and animal fats. For healthy whole fats: avocado, coconut, raw nuts, egg yolks, grassfed cheese if tolerated or a full-fat goat yogurt.

Daily totals

If you tally up your total carbs for the day during this adaption period they should likely be in the ballpark of 75-250 grams for most healthy athletes, but this doesn’t mean you can’t have more than that depending on your individual needs and activity level. For example, on extreme exercise days and race days, eat as much as you need, don’t measure anything, and do not force low carb. But on a sedentary rest day, you should feel ok and it should feel natural to have carbs as low as 75-100 grams for the day and not like your body is going crazy at this level.


If Overcoming Carb Dependence

This is largely about quality of carb choices. Avoid sugars, grains and most heavy starches for now (this is temporary), and certainly avoid junk foods (cheesecake doesn’t count as a carb refeed). Also monitor calories to ensure you’re not going chronically hypocaloric. In addition to calories, be sure to track carb intake using a food logging app, keeping daily intake to 70-150 grams a day, at most 200 grams, in these initial few weeks as your body adapts.

Option 1: Carb backloading

Stick to very low-carb fuel for breakfast, lunch and snacks (even if you worked out in the morning/daytime hours) and reserve the carb refeed for evening hours only. This is essentially carb backloading, and its also reported to work well for strength gains. At your evening meal: Don’t let it be a “free for all” with the carbs, and this may be a time where you have to implement a little willpower to overcome your craving for pasta and chocolate chip cookies and instead have spaghetti squash and berries with cream.

Option 2: Carb cycling

These are planned, calculated days of very low carb followed by a day with a carb refeed, which I cover how to do here. This tends to be very effective. For your carb days and sports nutrition needs, UCAN, again, is a good supplement to get in clean carbs without the blood sugar and insulin response!!!

Whatever you choose, you will most likely be cutting out some refined carbs and sugars, switching fuels, having a new grocery list, and feeling your body making a transition. Some experience headaches and icky symptoms for a couple weeks, and this is very normal, it’s your body transitioning and often releasing built up toxins. This is not a time to be drinking a lot of alcohol or eating out a lot, these will hinder results and make you feel worse.

Be diligent for 2-4 weeks or until you feel like you are free from carb/sugar dependence, your energy is steady (no extreme blood sugar fluctuations) and you are burning fat for fuel efficiently (How to know if you’re a fat burner? Listen here and read show notes for a checklist). Do not maintain this all-day low-carb approach ongoing especially during training—it’s just meant to be temporary to help you get over that hump and promote metabolic flexibility so that you’re no longer reliant on just sugar/carbs to function.


Periodizing & Coming Full-Circle

Eventually reintroduce more carbs with breakfast and other meals even if you’re not doing a mega workout right after—it’s ok! If you’re metabolically healthy your body can fully handle this, and it’s also mentally healthy to keep variety and not “fear” any one macro at any one time. Maybe you even need those carbs in the morning after previous tough workouts from which you’re still recovering.

Also, I can’t stress enough the importance of nutrition periodization for athletes. When you’re in offseason or when training is low, you can more likely get away with lower carb fueling. But as training ramps up you may need to pile on more carbs to support your training demands and recovery needs. I consider quality over quantity more important than how many carbs to eat or not eat. This doesn’t mean carb loading on just your big day, it may mean constantly eating higher carbs to stay ahead. It’s rare that a hard-training endurance athlete can get away with very low carb year-round, so plan your nutrition needs in accordance to your season.

Whether it’s carbs at breakfast vs. dinner or more carbs during peak training, the biggest take-away is that we all are different and you have to experiment to see how you feel and operate best, so don’t feel like there are definitive rules nor that it’s one-size-fits-all with your diet.

It is especially good for women to cycle in higher carb days starting with breakfast for balanced hormones; and also carbs earlier in the day help both men and women to maintain adequate adrenal function. That said, this does NOT mean eating refined carbs and high amounts of sugar at breakfast!!! So put down that donut and sugary bowl of cereal. Even adrenal-healing protocols will caution against high sugars and refined carbs in the diet. Your carbs sources should be clean, whole food sources that are generally lower on the glycemic index. Something like pumpkin oatmeal (soak your oats first) with blueberries, coconut milk with a couple eggs with runny yolks is fine. Or some protein pancakes with eggs. An omelet with sourdough toast and seasonal fruit works. Or you can’t go wrong with grain-free porridge made with sweet potato—athletes in training may also want to add UCAN for an extra punch. Search the breakfast section for more ideas.

I recommend at least once or twice a week having a carb-based breakfast regardless of your training load. You can of course plan this in conjunction with your training—maybe before a long day or the day after a big workout where no matter what you ate, you burned through it and wake up hungry. But at the same time, don’t let yourself get too obsessed with only allowing carbs with training—that’s a dangerous path.

High-carb breakfasts still need good fats and protein (not just a bagel and jelly), and this is also to help prevent a huge spike in blood sugar to ensure you maintain steady energy not a spike then crash. Side note: the bagel/donut-approach fails every time because you get high off the sugar then crash by 10am, go for more sugar and the vicious cycle continues.


Example Daily Macro Breakdown:

  • Carbs – 20-40%
  • Fat – 30-60%
  • Protein – 20-30%

…These numbers can and should vary as much as they need, and it’s not like you pick your ratios and stick to that indefinitely. The boy is always changing, what you’re doing and needing is always changing, so you must be able to adapt with your needs and be intuitive.

Also, keep in mind that athletes need anywhere from 2,500-5,000 calories a day, so you can do the math based on your needs and most of all, no matter your macros or fat-burning abilities, DO NOT UNDERFUEL!

The important thing is to listen to your body rather than follow a template. Some days you may be hungrier, so eat more! That’s ok! (Whether that’s before or after training.) Other days you’re not as hungry so don’t force food, and make those an opportunity to test your carb timing and fat fueling for improved fat oxidation.


Being Specific To YOU

That said, intuitive eating sometimes fails us, it can be a tough thing to master, I get it. So what do you specifically need? My best advice is to hire a coach who also does nutrition planning or a sports nutritionist to go through your profile and best determine your fueling needs when we’re talking calories and macros pre, during and post workout.

A shameless plug: I do this work with my athletes and also via consultations—i.e. you don’t have to hire me as your full-time coach; instead, a consult is like an a la carte service to hone in on your needs, like nutrition.

Everyone is different! Don’t get stuck doing what your friend is doing just because it looks right and works for him. Don’t get stuck on the numbers, either. You are a human and your needs are always evolving, by the hour and by the day. It’s important to feel in control of your metabolism but be able to work with it not fight what your body is saying.


Practicing for Race Day

You need to prepare the body to handle food and calories on race day, and this practice starts in training. You should be practicing race-specific fueling at least once a week on long workouts during your specific training phase (i.e. 10-16 weeks before race day). A few times you’ll want to do a specific run through of all your nutrition, starting with dinner the night before and breakfast the morning of, exactly how you’ll do it on race day and also doing an extra long workout (long brick or 20-mile run, etc.). The longer the race, the more important this is to practice and I like my athletes to do the full shebang at least 3-5 times before a big A race.

The dinner the night before should be well-planned, that is, make something that ideally and realistically you would be able to eat the night before a race (don’t get takeout from your favorite local joint that would be impossible to replicate at the race location). Avoid traditional carb loading—see our LPC article on that here. You also don’t need to gorge yourself with calories while you’re less active and tapering; you don’t want your digestive system having to work so hard that night when instead you should be resting (yes asking too much of your digestive tract can disrupt sleep). So think, reasonable portions, e.g. 2 chicken thighs, small side of veggies or salad, roasted sweet potato with butter and cinnamon, normal serving of quinoa, a smear of avocado… you get the idea.

Race morning breakfast? Folks, it just depends what you like. Examples are provided in the LPC recipe section. This may be trial and error and it’s mostly about what you feel good eating—and what you can get down while nerves increase. It’s important to keep it relatively simple and items that are known to digest well in your system (don’t sabotage your race performance!), and there’s no right or wrong answer because it is highly individual. Some athletes love high-fat smoothies while some get nauseous just thinking about that before a race… try, experiment, practice in training or your low-priority C races.

Your fat adaptation should be well developed in your other workouts so this breakfast can allow for a bit more carb if you like that, and probably a good idea for long-course or super high-intensity races. I was always well fat adapted and really dialed in, and I would always eat oatmeal for breakfast on race day—it didn’t not screw up my fat burning on long event like 70.3’s. It really doesn’t matter to eat more carbs in an acute sense like that.