Food is fuel. As we’ve focused more on the relationship between what we put into our bodies and how we perform in the gym or on the road, it’s become widely accepted that nutrition is a core piece of the performance puzzle. While it’s easy to rely on foods that can boost our performance in the short term, though, thinking about the longer-term nutritional decisions an athlete can make to boost performance every day is tougher. Ultimately, when it comes to these more impactful decisions – and the science that underlies them – there simply isn’t a lot of noise out there.

While we’ve spent the past few months focusing on physical feats and mental strength, it’s time to turn to the linchpin of both of those. That’s why this month, we’re working with chef and restaurateur Seamus Mullen to dig deeper into the role that food plays in allowing us to perform at our highest level.


A three-time James Beard award semifinalist, Seamus Mullen is a thought leader in the food industry. He’s cooked in some of New York City’s top restaurants, been named a finalist on the Food Network’s “The Next Iron Chef,” and opened restaurants that have garnered critical acclaim. In addition to his success as a chef and restaurateur, though, Seamus has also become a leading voice on health and wellness.

Although Seamus was an avid cyclist who raced competitively in his twenties, he embraced an unhealthy lifestyle while putting in the work as a young chef in New York City. This lifestyle – filled with late nights, frequent meals, and an unhealthy diet – landed him in the ICU in 2007, when he was diagnosed with rheumatoid arthritis. However, following his diagnosis, Seamus committed to making food – the very thing that almost killed him – a key partner in his journey to recovery.

Today, Seamus isn’t about following the latest fads or constantly withholding pleasure in the name of healthy eating. Instead, he focuses on striking the delicate balance between using food to improve performance and ensuring that food remains something that we view in a positive light. A leading authority in the conversation on food, health, and wellness, Seamus has mastered the ability to use food for fuel.

this month

Over the next four weeks, Seamus will be sharing the tips, recipes, and science behind a successful and performance-oriented diet. Instead of talking about “miracle solutions” that are more hype than results, he’ll share his carefully researched and science-based approach to finding the right foods and eating them the right way. Covering topics ranging from the reasons to consider a Keto or High Carb diet to how hydration fuels performance to food’s effect on recovery, it’s time to focus on the often-overlooked core element that underlies our physical and mental performance alike: nutrition.

An award-winning chef and restaurateur and former competitive cyclist, Seamus Mullen is an authority on the complex relationship between health, fitness, and food. With the expertise he’s gained from decades on the road, in the gym, and in the kitchen, Seamus will be sharing his expert opinions and insights as he guest-writes our Better Than Yesterday series for the month of September. This week, he’s weighing in on the High Carb vs. Keto debate.

Today, there are few approaches to nutrition that spark as fierce a debate as the discussion of Keto Vs. High Carb. As someone who is inherently curious about nutrition and the impact food has on both our health and performance, I’ve experimented with everything from a raw vegan approach to LFHC (low-fat, high-carb) to LCHF (low-carb, high-fat). Over the course of this process and my time as a professional chef, I have learned a lot. Some of what I’ve experienced jives with popular science, but some doesn’t. More than anything, I’ve learned there really isn’t a one-size fits all when it comes to food. That said, there is a vast gap between going LFHC and committing to keto, and where you decide to sit on the spectrum can greatly impact your athletic performance and recovery.

Before we dive into the performance impacts of each diet, here are the basics. Low-fat, high-carb diets are self-explanatory; they include a lot of grains, veggies and fruits at the expense of meats, cheeses and fats. Keto is a little more complex. Going keto is about the pursuit of ketosis. In the simplest form, ketosis is a state in which the body starts using its own fat storage as a fuel. When carbohydrates are restricted, the body reverts to a secondary energy system, breaking down fat in the liver and converting it to ketones, a fatty-acid byproduct, that is then used to replace glucose. Basically, it’s a focus on more protein and fat while restricting carbs to train your body to use its own fat stores as fuel. Between these two extremes, but closer to keto, is the more mild LCHF (low-carb, high-fat) diet.

As with all nutritional approaches, it’s important to factor in the athletes’ goals. Are they weight loss? Endurance and recovery? Muscle growth? All of the above? To be clear, both systems can help achieve many of the same outcomes, depending on the person and how their bodies process food. However, there is a good deal of data and testing in recent years pointing towards lower carb diets like LCHF and keto having performance advantages for workouts and recovery.

As a fueling system, many endurance athletes find that, once they switch to Keto or LCHF (high-fat, low-carb), they are able to consume less during endurance workouts and competitions. When I’m on a High-Carb protocol, particularly right before a workout, I have to continue to stoke my system with carb-rich foods or my blood sugar starts to plummet. However, I don’t face this issue when I’m consuming fewer carbs daily. For this very reason, I find that my body works best when I alternate between periods of strict Keto and the more mild LCHF, which keeps me in mild ketosis. For periods when I want greater mental clarity and energy (Think a more realistic version of Bradley Cooper in “Limitless”), as well as a quick trim down, I lean harder into Keto. When I’m maintaining and still want to keep inflammation low, I’ll gravitate more towards a light LCHF protocol. That said, I also have friends who are much leaner than I am, and if they stay in prolonged periods of ketosis, they end up leaning out too much, which can increase recovery time and have a negative effect on hormones. This is what I mean by there not being a one-size fits all approach!

While it’s pretty widely accepted that Keto works quite well for HIIT training, it seems that we are going to continue to see more and more exploration of the Ketogenic diet for endurance athletes as well. In cycling, my preferred endurance sport, I’ve watched year-by-year over the past ten years as more and more Pro cycling teams shift towards a LCHF/Keto protocol for their athletes. This means they are eating less on the bike, recovering more quickly, and reducing inflammation markers.

In general, the conventional wisdom of yesteryear that dictated “carb-loading” and then stoking the furnace as we work out (think plates of pasta the night before a bike race, followed by a steady stream of syrupy goop throughout the race) is slowly being upended. Can you work out hard and long on a HCLF diet? Yes. And if you’re burning 5-10k KJ in a workout, you’ll still be in a caloric deficit, but at what cost? The inflammation that comes with a high-carb diet increases recovery time, and the ongoing metabolic stress can have long term negative effects on our health. Ever hear of the skinny-fat marathon runner that drops dead of a heart attack? Or know of an older endurance athlete who is not overweight, but depends on statins to maintain healthy cholesterol numbers? More often than not, the common culprit is years of following the LFHC protocol of the Standard American Diet (SAD).

Adhering to a LCHF diet is pretty easy, and there are tons of resources available to keep it interesting in the kitchen. When it comes to strict Keto, though, a lot of folks can get tripped up. I like to think of it as a tool to use during specific periods, and I’ve found that the more I’ve done Keto, the easier it becomes for me to dip in quickly and without the negative initial side effects. When I’m following a strict Keto plan, I tend to create a very basic meal plan and stick to it. I check my fasting glucose and fasting ketones first thing in the morning, and I adjust my macros accordingly. A sample day looks like this:

5:30 AM
Wake up, drink water.

6:00 AM
keto coffee (I drink brewed coffee and whisk in
BUBS Naturals MCT powder)

6:45-9:15 AM
Fasted work-out

12:00 PM
3 egg omelet with cheese, butter, bacon, avocado, scallions, greens

6:00 PM
Lamb burger, avocado mayo coleslaw, olives, no-sugar pickles and a handful of frozen macadamia nuts.

While no size fits when it comes to recommending optimum diets, it’s clear that the conventional wisdom of the past -- one that pushed a high-carb, low-fat diet -- certainly doesn’t fit all athletes in anaerobic sports, and it may even be less beneficial than previously thought in aerobic endurance sports. It may require some experimentation, but trying out a new balance of carbs, proteins and fats in your diet may be just what you need to take your performance to the next level.

An award-winning chef and restaurateur and former competitive cyclist, Seamus Mullen is an authority on the complex relationship between health, fitness, and food. With the expertise he’s gained from decades on the road, in the gym, and in the kitchen, Seamus will be sharing his expert opinions and insights as he guest-writes our Better Than Yesterday series for the month of September. This week, he’s digging into hydration.

The human body is 60% water. Every human function – including athletic performance – relies on being properly hydrated. However, we too often deprioritize the liquids going into our body, instead drinking only when we’re thirsty. This is a crucial mistake, as improper hydration severely impairs our body’s performance. When we’re putting in work, sweating causes our body-water levels to drop. In turn, our blood thickens, which slows down delivery of oxygen-rich blood to our muscles. By the time we notice that we’re thirsty, we’re already performing at below our optimal levels. It’s time we start taking hydration more seriously.

Since low body-water levels are a key performance inhibitor, starting our work sufficiently hydrated is a must. When you aren’t actively pre-hydrating or are working out in warm-weather conditions, it’s easy to get into a hydration deficit that’s nearly impossible to climb out of. That’s why, especially before hard workouts, the focus must be on getting water into our system and on “‘plenishing” before you “replenish” from the very beginning. In my mind, a good rule of thumb is to target a minimum of 8-16 oz of hydration per hour in cool to temperate environments, and as much as 30 oz of hydration per hour in hot environments. Furthermore, this water shouldn’t all be taken down at once. Instead, I’m a fan of the “slow drip” approach of drinking water throughout the day, as over-hydrating at the beginning of a workout hurts performance and slows you down. It’s easy to overlook, but being proactive about staying hydrated is key for putting in quality work. Without staying hydrated from beginning to end of a hard effort, the delivery of oxygen-rich blood becomes more and more compromised, which in turn leaves us with a rising heart rate while our power output plateaus.

However, with more strenuous exercise, water is not sufficient to effectively hydrate. This is where hydration solutions come into play. These solutions – which replace the sodium, potassium, magnesium, and other electrolytes that are lost through perspiration – are not created equal. A product that touts its electrolyte-replenishing benefits doesn’t do much if it’s also loaded with unnatural and extraneous ingredients. That’s why it’s good to look for products that are low-to-no sugar and have low osmolality. Osmolality refers to the concentration of all chemical particles (solutes) found in a solution, like our blood or a sports drink. The more particles that are in a liquid, the higher its osmolality. The typical sports drink has an osmolality of 300-305mOsm, whereas our blood sits around 285mOsm. Thus, the osmolality of the typical sports drink is too high, which inhibits hydration. If your electrolyte solution’s osmolality is higher than that of the blood, the liquid you consume will remain in the stomach – even if the particles themselves are healthy chemicals. When this happens, instead of the solution passing through to the intestinal tract to be absorbed by the body and utilized by your active muscle groups, the stomach will actually pull water from other parts of the body to lower the solution’s osmolality, which paradoxically results in increased dehydration. So should you avoid sports drinks all together? Not necessarily. While you might not be able to see your favorite beverage’s osmolality on the label, you can make a safe bet that by avoiding sports drinks that utilize maltodextrin and fructose as their carbohydrate sources. In doing this, you’ll ensure that the liquid you consume will hydrate you, not deplete you.

While hydration is undeniably a critical part of the performance puzzle, everybody’s exact hydration needs are different. One of the most useful tools for developing a successful hydration strategy that works for how you train is a sweat test. At its most basic level, a sweat test measures the amount of fluid you lose per hour of exercise. With only a dry towel and a kitchen scale, you can measure and understand the amount of fluid you lose per hour and what you can safely replenish on an hourly basis. For example, I sweat a lot, often losing in excess of one pound of water weight for every hour of hard exertion in a hot environment. Having determined this, I know that in my toughest workouts, it is extremely important for me to pre-hydrate with water, drink 16 oz (or ideally 32 oz) of a hydration solution during the workout, and then slowly sip a hydration solution for the next hour post-workout. Knowing how much fluid I use when I’m putting in the work has been key in helping me boost my performance, and it’s easy for you to figure out what’ll work for your body. Here’s how I figured it out:

  1. Go for a pee and then record your body weight, ideally with no clothes on (that’s A).
  2. Perform your session (or event) and record exactly how much you drank. This is easy if you drink from a single bottle or two; simply weigh your bottles before you exercise (that’s X) and after (that’s Y) and record the difference (that’s Z). 1 gram = 1 milliliter.*

*Make sure all units are in kg or liters

  1. After exercise, towel yourself dry and then record your weight (that’s B). Again no clothes on is best, as your clothes will hold some sweat.
  2. Now subtract your post-exercise weight (B) from your pre-exercise weight (A) to get the weight you lost during the session.

Weight lost (C) = A-B

  1. Also subtract the weight of the bottle(s) before (X) and after (Y) to obtain the amount you consumed (Z).

Volume consumed (Z) = X-Y

  1. You can now calculate your sweat rate: Weight lost + volume of liquid consumed / time spent exercising. Or, simply: (C+Z) / time.

Armed with your sweat rate, you have a better understanding of how much fluid you lose during an hour of exercise. While it’s almost impossible to replenish all the fluid that you’re losing - especially if you’re a heavy sweater like I am — you’ll want to aim for around 56-75% of fluid replenishment each hour. For example, if you’re sweating out 50oz (1.5L) of fluid every hour, you’ll want to try to take in about 1L of fluid - ideally with electrolytes — each hour of exercise. For context, the standard bike water bottle is around 0.75L, which means one full bottle + a few pulls from your second bottle should do the trick.

The simple truth is that even though it can feel like an afterthought in the nutrition conversation, hydration is a key part of the performance puzzle that deserves more attention than it’s currently given. Whether it’s before, during, or after your workout, proper hydration ensures that you’re getting out what you’re putting into your sessions. However, while hydration seems easy to figure, there isn’t a one-size-fits-all approach. That’s why figuring out your exact hydration needs, finding the solutions that allow you to create a successful hydration strategy, and being able to adjust to account for environmental changes is critical to improving recovery and performance through every workout.

An award-winning chef and restaurateur and former competitive cyclist, Seamus Mullen is an authority on the complex relationship between health, fitness, and food. With the expertise he’s gained from decades on the road, in the gym, and in the kitchen, Seamus will be sharing his expert opinions and insights as he guest-writes our Better Than Yesterday series for the month of September. This week, he’s digging into hydration.

Over the past few weeks, Seamus Mullen has led us through a deep dive into the relationship between what we put into our bodies and how we perform. Now that he’s shown us the science underlying the nutritional axioms we often take for granted, it’s time to focus on its practical applications. That’s why this week, Seamus is giving you the solutions you need to ensure you’re fueled before, during, and after your workout.

pre-workout: coconut roasted sweet potato (SERVES 2)


1 medium sized sweet potato

1 TBSP coconut oil

1 TSP maple syrup

Chili Powder to taste

Zest and juice of 1 lime

Cilantro and mint, chopped to garnish

1 TBSP unsalted butter

Coarse sea salt


Pre-heat oven to 400 F

Place the whole sweet potatoes on a roasting tray and roast until tender and cooked through, about 30 minutes, depending upon size.

Remove from the oven and cut sweet potato in half length-wise.

Turn oven to Broil.

Rub each half of the sweet potato with 1/2 TBSP coconut oil and 1/2 TBSP butter, then drizzle with maple syrup. Season with sea salt to taste and return to broiler for 3-5 minutes until slightly browned and caramelized.

Finish with a sprinkle of Chili Powder, a squeeze of lime juice and lime zest and a sprinkling of the chopped herbs. Serve immediately.


during workout: tropical energy bar (MAKES 12 BARS)


2 cups unsalted macadamia nuts

2 cups no-sugar-added dried pineapple

1 cup dried unsweetened coconut flakes

2 TBSP coconut oil

1/4 cup cacao butter

1 TBSP chia seeds

1 TSP coarse sea salt


Combine all of the ingredients in a food processor. Pulse until the mixture resembles a dry cookie dough. If you need to add a little moisture, drizzle in a small amount of cold water.  

Spread the mixture on a medium sized cookie sheet lined with plastic wrap. Cover with plastic wrap and press firmly into an even layer.

Using a sharp knife, cut into 12 bars. Wrap each individually with wax paper or plastic wrap.



¼ cup EVOO from Spain

1 zucchini, cut into chunks

1 Summer squash, cut into chunks

½ cup mixed cherry tomatoes

1 bulb fennel, thinly sliced

1 lemon, thinly sliced, seeds removed

1 cup green beans, cut into 1” pieces

Small bunch of ramps or scallion bulbs, plus greens thinly sliced

2 cloves garlic, grated

2 wild salmon filets, 6oz each

Salt, pepper and lemon zest

1 TSP harissa powder or smoked paprika

A handful of fresh herbs like basil, tarragon or Summer savory


Pre-heat oven to 350F.

In a large roasting pan combine all the vegetables, season thoroughly with salt, pepper and harissa powder and toss with olive oil.

Season the salmon with salt and pepper and top with a few slices of lemons, nestle on the vegetables and roast in the oven for 18 minutes.

Serve with a drizzle of fruity Extra Virgin Olive Oil from Spain and fresh herbs, I like to use basil and tarragon, but any bright herbs will do!