How To Fuel The World’s Hardest Home HIIT Workout | Boss Level By Fiit

High intensity interval training (HIIT) is one of the most effective and efficient forms of training you can do to improve your physique, performance and overall fitness. 

It’s also a staple training form used within many of the world’s best athlete training programmes. 

We’ve partnered with HIIT enthusiasts and experts, Fiit, who are soon to be launching the world’s hardest home HIIT workout, Boss Level by Fiit – a 90-minute class designed to push you to your limits and into that next echelon of health and fitness. 

They’ve challenged us to draw up the perfect nutrition plan around training and to fuel you throughout these next few weeks.  

Our in-house nutrition experts have accepted, and are ready to present to you the methods you should follow to get the most out of Fiit’s challenge.


The importance of nutrition around exercise

Interval training is taxing on the body and, depending on the duration, intensity and environment of the activity, can result in: 

  • reductions and or depletion of existing glycogen (your internal carbohydrate) stores1 
  • fat breakdown and oxidation2 
  • muscular breakdown3 
  • reduction in circulating electrolyte levels and hydration levels4 

If you don’t address these factors by eating and recovering well, then you can forget a strong performance in your next Boss Level workout.  

The purpose of your nutrition strategies around training should be to: 

  • Spare glycogen (by providing a readily available alternative) and restore it following a training session.
  • Reduce proteinbreakdown (for use as an alternative energy source)
  • Increase muscle protein synthesis(the creation of new muscle protein)
  • Restore any loss in electrolyte levels/ preserve electrolyte levels 
  • Optimiseyourhydration status and, ultimately, avoid dehydration 

You can attack each and every one of these points by adapting your nutrition around training. Following the next few steps will allow you to stand more than a fighting chance against Fiit’s gruelling challenge.


Pre-workout strategies

Pre-workout nutrition can mean any time between the last time you exercised and the present session, however, we’ll be referring to within sixty minutes of starting training. It should be geared towards providing a readily available source of energy (typically carbohydrate). 

When we say “readily available” what we mean is simply a source of energy that’s already, or is quite simply and quickly, broken down. Your body’s cells thrive best on glucose (which is the smallest form of carbohydrate and the most readily available) which is why carbohydrates, particularly “sugary” carbohydrates, are best — especially for interval training. 

Nature has already perfected pre-workout nutrition in the form of the humble banana – a readily available carbohydrate, rich in electrolytes and relatively low in calories. Dried fruit is another great alternative, or even a handful of sweets are fine. 

If you really want to get the most out of your interval training though, you may want to consider a caffeine-based pre-workout supplement. Caffeine is the greatest performance enhancing supplement we have available, effective at boosting our performance as well as flicking the ignition to supercharge our fat burning efforts.5 

Our new Pro Range includes THE Pre-Workout+, an expertly crafted and industry-leading package of caffeine, beta-alanine (which helps support performance by buffering lactic acid) and an unparalleled dosage of l-citrulline (critical to supporting blood flow to and from the working muscles).6,7 

Not only that, but it also contains green tea extract (for additional fat burning purposes) as well as electrolytes and B vitamins which can help support energy production.

shaker full of THE Pre-Workout+ and a banana or handful of dried fruit? Sounds like a recipe for the best session you’ve ever had. 


Mid-exercise considerations

During training your focus should be to continue to provide yourself with readily available carbohydrate if you plan to train any longer than one hour.8 

You may want to bring a ready-made carbohydrate mix and or one or more carbohydrate gels. These can both preserve your glycogen stores and fuel your workout effectively. 

Fluid intake is also critical during training to avoid the nasty effects of dehydration. This becomes even more important in the heat. Many will go overboard on their intra-workout fluids however and needing to visit the bathroom during interval training is certainly an unwanted disruption.  

The perfect amount of liquid? Try to sip on between 300 – 500ml of water per 30 – 60-minute worth of work (going with the flow of what suits you… pun fully intended). 

One addition worth considering would be incorporating amino acids and or branched chain amino acids (BCAAs) into your intra-workout routine. Amino acids may be able to delay time to fatigueimprove concentration, and reduce some of the muscle damage caused by intense exercise. caused by intense exercise.9,10 

We’ve launched “THE Amino+”, a patented blend of gradual release, hyper absorbable amino acids and BCAAs. Designed to help you get every last ounce out of a workout, we’d recommend adding this to your stack, especially for the Boss Level challenge! 


Post-workout strategies

Post-workout nutrition is arguably the most important of the three stages for recovery.  

The focus here is on everyone’s favourite; protein. 

We’re aiming to get between 20 – 40g of high-quality protein (sources of protein rich in, as well as containing the full spectrum of essential amino acids). 

One of the more crucial amino acids to consider is leucine. Leucine “turns on” muscle protein synthesis and we’d be aiming to get at least 3g in that post-workout meal (which would fall within that 20 – 40g serving range for virtually all sources).  

Protein source is important and if you’re after the widely considered “best” protein source, then look no further than whey protein. Whey protein is the highest quality protein we’re currently aware of and is jam packed full of essential amino acids, and one of the best sources of leucine. 

Striving for the perfect protein powder supplement has been an ambition of Myprotein since our inception. With the release of “THE Whey+” we’ve gotten one step closer. 

If you’re trying to level up your performance and deciding on which whey protein to opt for then you must give this one a try. There’s no substitute for the quality of our whey source and the patented blend of whey protein isolate, hydrolysed protein and micellar casein that you’ll find in THE Whey+. 

This blend instigates a rapid onset of muscle recovery processes whilst providing a consistent stream of building blocks to continue this process thanks to the PhaseTech™ technology. 

Depending on the overarching goal of your diet, and if your calorie target permits, an equal half serving of readily available carbohydrate would be a great post-workout addition helping to replenish any lost glycogen, and even prevent muscle protein breakdown. Sticking to the carbohydrate options we outlined earlier would be your best bet here. 


General considerations

Getting your nutrition protocols around exercise right is one of the major advantages you can have to beating Fiit at their own game, but what you do the rest of the day is also critically important to your performance and recovery. 

It goes without saying you want to stay on top of your sleep and have an established routine that compliments your efforts. You also want to focus on minimising stressors in your life that could inhibit your recovery and performance. 

Diet wise, you should be aiming to achieve a higher protein and higher carbohydrate diet whilst keeping your fats lower. 

The Academy of Nutrition and Dietetics (AND), Dietitians of Canada (DC), and the American College of Sports Medicine (ACSM) recommend that you should consume 5 – 7g of carbohydrate per kilogram of bodyweight per day (g/kg/day) if you’re engaging in activity like interval training.11 

The International Society of Sports nutrition recommends that athletes should aim to achieve 1.6 to 2.2g of protein per kg of bodyweight per day to support the increased demands of intense exercise, optimise muscular adaptations and improve or maintain body composition.12 

If it’s practical for you, it may be worth having a health “safety net” in your back pocket in the form of a multivitamin. THE Multi™, another new product within our pro range, is a compilation of the A-Z of vitamins and minerals you need in a highly bioavailable package. Multivitamin users need to add this to their pantry. 


Take home message

Fiit have laid down the gauntlet with Boss Level, but with the strategies we’ve laid out, you’ll be able to meet the ‘world’s hardest home HIIT workout’ challenge head on. 

Your nutrition around training is important but do not overlook that the 22-23 hours outside of your workout will define your success. 

Incorporating our range of pro products will certainly help too — industry leading supplements geared towards helping active individuals achieve that best version of themselves. 

So, what are you waiting for? Go smash Boss Level by Fiit. 

Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you’re concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

  1. Baker, J., Buchan, D., & Graham, M. (2016).High intensity exercise and glycogen depletionSingle Cell Biology. 
  2. Astorino, T. A., & Schubert, M. M. (2018).Changes in fat oxidation in response to various regimes of high intensity interval training (HIIT)European journal of applied physiology118(1), 51-63. 
  3. Meckel, Y., Nemet, D., Bar-Sela, S., Radom-Aizik, S., Cooper, D. M., Sagiv, M., & Eliakim, A. (2011).Hormonal and inflammatory responses to different types of sprint interval trainingThe Journal of Strength & Conditioning Research25(8), 2161-2169. 
  4. Casa, D. J. (1999). Exercise in the heat. I.Fundamentals of thermal physiology, performance implications, and dehydrationJournal of athletic training34(3), 246. 
  5. Guest, N. S.,VanDusseldorp, T. A., Nelson, M. T., Grgic, J., Schoenfeld, B. J., Jenkins, N. D., … & Campbell, B. I. (2021). International society of sports nutrition position stand: caffeine and exercise performanceJournal of the International Society of Sports Nutrition18(1), 1-37. 
  6. Hobson, R. M., Saunders, B., Ball, G., Harris, R. C., & Sale, C. (2012).Effects of β-alanine supplementation on exercise performance: a meta-analysisAmino acids43(1), 25-37. 
  7. Kerksick, C. M., Wilborn, C. D., Roberts, M. D., Smith-Ryan, A., Kleiner, S. M., Jäger, R., … & Kreider, R. B. (2018).ISSN exercise & sports nutrition review update: research & recommendationsJournal of the International Society of Sports Nutrition15(1), 1-57. 
  8. Vitale, K., & Getzin, A. (2019).Nutrition and supplement update for the endurance athlete: review and recommendationsNutrients11(6), 1289. 
  9. Gualano, A. B., Bozza, T., Lopes De Campos, P., Roschel, H., Dos Santos Costa, A., LuizMarquezi, M., … & Herbert Lancha Junior, A. (2011). Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletionJ Sports Med Phys Fitness51(1), 82-8. 
  10. Kim, D. H., Kim, S. H., Jeong, W. S., & Lee, H. Y. (2013).Effect of BCAA intake during endurance exercises on fatigue substances, muscle damage substances, and energy metabolism substancesJournal of exercise nutrition & biochemistry17(4), 169. 
  11. Vitale, K., & Getzin, A. (2019).Nutrition and supplement update for the endurance athlete: review and recommendationsNutrients11(6), 1289. 
  12. Jäger, R.,Kerksick, C. M., Campbell, B. I., Cribb, P. J., Wells, S. D., Skwiat, T. M., … & Antonio, J. (2017). International society of sports nutrition position stand: protein and exerciseJournal of the International Society of Sports Nutrition14(1), 1-25. 

Jamie Wright

Jamie Wright

Writer and expert

Jamie Wright holds an MSc Degree in Human Nutrition and a BSc (Hons) in Sports and Exercise Science, and now works with multiple organisations as well as running his own private nutritionist coaching services company, OUTWRK, to help individuals with their nutritional goals. He is accredited with the Association for Nutrition and has helped hundreds of clients; from those with eating disorders to internationally competing athletes. Jamie supports his clients with evidence-based, holistic nutrition programming to reach their health and fitness goals. In addition to running his practice, Jamie regularly contributes to the field of nutrition presenting and writing on its many facets. He has had his research presented at the UK Obesity Congress as well as overseas conferences and has authored several e-books whilst contributing to others (including charitable sporting organisations). His research has centred around weight management as well as sports / exercise performance and supplementation. A massive sport nut, avid gym goer and lover of all things dog related, Jamie’s goal in sharing the experience and knowledge he has gained academically and professionally is to provide a source of clarity in the vast amount of “misinformation and noise” that exists within the health and fitness industry. You can check his work out further at OUTWRK or @jamiesdietguide on social media.

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