Why Digestibility Matters When Choosing Fuel Bars That Power Workouts and Aid Recovery

Why some snack bars sit in your stomach like a brick and others power you smoothly through a session, comes down to one core idea: digestibility. Oat-based fuel bars, when built with the right ingredients, provide a steady release of carbohydrates that support performance and recovery without the blood sugar spikes, crashes or gut discomfort many athletes know too well.¹

Below, you will learn what digestibility really means, why dates and oats are such a smart base for fuel bars, and how MARCHON fuel bars are designed to deliver natural, stomach-friendly energy for both workouts and recovery.

Digestibility is about how efficiently your body can break down and absorb the nutrients in a food without causing gastrointestinal distress.² In the context of fuel bars, highly digestible bars:

• Provide carbohydrates that are broken down at a controlled rate.¹

• Avoid excessive gut fermentation, bloating or cramping during exercise.³

• Deliver protein and fats that are accessible to digestion, not locked away in overly dense or heavily processed matrices.²
  
  

Poorly digestible bars, in contrast, often combine dense textures, excessive fibre, hard-to-digest proteins or sugar alcohols, which can slow gastric emptying and trigger gas, cramping or an urgent dash to the toilet mid-session.²⁸

MARCHON's chocolate and raspberry oat fuel bars are built on gluten-free oats, rice syrup, date paste, coconut oil and brown rice protein, ingredients chosen to be recognisable, plant-based and gentle on the gut, while still supporting performance-focused nutrition.

Oats are one of the most useful carbohydrate bases for active people because they naturally combine starch with soluble fibre, particularly oat β-glucan.¹

A major systematic review and meta-analysis of acute feeding trials found that adding oat β-glucan to carbohydrate-containing meals reduced:

• Post-meal glucose incremental area-under-the-curve by ≈23%.¹

• Peak blood glucose by ≈28%.¹

• Insulin responses by ≈22–24%.¹²⁰

This slower digestion and absorption means:

• More stable blood sugar and insulin levels.¹⁹ ²⁰

• Less of the “spike–crash” pattern associated with some high-sugar snacks.¹⁹

• A more sustained supply of fuel during training or between sessions.³⁰
  

For athletes, that translates into smoother, longer-lasting energy rather than a sharp burst followed by a slump.

MARCHON’s fuel bars leverage this by using gluten-free oats as the primary carbohydrate source, supported by rice syrup, date paste and maple syrup. 

These provide quickly accessible carbohydrates layered on top of the slower-release effect of oat β-glucan—a combination that suits pre-workout fuelling, mid-session top-ups and post-training glycogen restoration.³⁰

Digestible carbohydrates are central to endurance and high-intensity performance. A recent narrative review on carbohydrates and endurance exercise highlighted that mixed carbohydrate foods such as oats, honey and dried fruits are effective pre-exercise fuel options and can improve time to exhaustion when consumed 30–60 minutes before training.³⁰

For recovery, the goals are to:

• Replenish muscle glycogen (your stored carbohydrate).³⁰

• Provide protein to support muscle repair and adaptation.²⁷

• Avoid gastrointestinal upset that might compromise appetite or subsequent sessions.²⁸
  

Oats bring more than just carbs to this equation:

• Oat protein and oat-derived components have been shown in experimental and human studies to help reduce exercise-induced muscle damage, inflammation and loss of performance after eccentric exercise.²¹ ²⁷

• Oat-based meals consumed before high-intensity interval training have been reported to mitigate exercise-induced oxidative stress and support better glucose handling around exercise.²⁴
  

By combining gluten-free oats with brown rice protein, MARCHON fuel bars offer:

• A digestible plant protein source that supports recovery without the heaviness of some high-fat or fibre-overloaded snacks.²² ²⁵

• Oat-based carbohydrates that can be used both pre-session (for fuel) and post-session (for recovery), depending on your timing and overall intake.³⁰
  
  

Not all “energy bars” are designed with the exercising gut in mind. Common problems include:

• Overly dense matrices and fibre loads
  Some high-fibre or protein bars use combinations of isolated fibres, mycoproteins or very high plant protein levels that reduce protein digestibility and slow breakdown in the gut.²² ²⁵ This can lead to gas, bloating and a feeling of heaviness during training.
  
  

• Sugar alcohols and obscure sweeteners
  Polyols (like sorbitol, maltitol) frequently used in “low sugar” bars can be poorly absorbed and ferment in the colon, contributing to cramping and loose stools in sensitive individuals, particularly under exercise stress.²⁸
  
  

• Highly processed protein blends
  In vitro studies and bar surveys show that bar formulations and protein sources strongly influence digestibility, with some plant-only formulations showing markedly lower digestibility compared to simpler matrices.²² ²⁵
  
  

MARCHON fuel bars deliberately avoid sugar alcohols and unnecessary processing complexity. Instead, they rely on:

• Gluten-free oats.

• Rice syrup and maple syrup.

• Date paste and freeze-dried raspberry.

• Brown rice protein.

These ingredients are chosen to be both natural and compatible with the digestive demands of training.

Taste, texture and performance: how MARCHON fuel bars balance all three

Digestibility is not just a lab concept, it is also tied to how a bar feels in your mouth and stomach.²² ²⁸ Good sports nutrition should be something you actually want to eat consistently.

Marchon’s chocolate oat bars and raspberry oat bars are structured around:

• Oats as the backbone
  Gluten-free oats provide the chew and carbohydrate base, contributing β-glucan for glycaemic control and satiety.¹⁹ ²⁰

• Simple, recognisable binders
  Rice syrup, date paste and maple syrup bind the bar, offering rapid and medium-speed carbohydrate fractions without relying on artificial thickeners or sugar alcohols.²⁸
  
  

• Fats that sit light
  Coconut oil supplies fats that help texture and mouthfeel while remaining relatively easy to digest for most people during everyday training.²⁸
  
  

• Targeted inclusions for flavour and enjoyment
  
  

  • Chocolate oat bars: organic dark chocolate with coconut blossom sugar chips plus gluten-free cereal balls create crunch and a satisfying chocolate profile without overloading sugar alcohols or emulsifiers.
    
    

  • Raspberry oat bars: flavoured cocoa butter, rice-based white chocolate-style pieces and freeze-dried raspberry deliver sweetness and acidity that make the bar enjoyable pre- or post-session.
    
    

The result is a fuel oat bar designed to:

• Break down efficiently in the gut.²⁸

• Provide a mix of quick and sustained carbohydrates.¹⁹ ²⁰ ³⁰

• Support both performance and recovery, without compromising on taste.

To get the most out of a well-designed oat energy bar:

• Pre-workout (30–90 minutes before)
  A fuel bar can top up liver and muscle glycogen and provide steady blood glucose, especially for morning or lunchtime sessions where your last meal may be several hours away.³⁰
  
  

• During longer sessions (60–120+ minutes)
  For runs, rides or endurance-style gym sessions, an oat-based bar can serve as a portable, more “real food” alternative to gels, especially at lower intensities where gut blood flow and digestion are better maintained.³⁰
  
  

• Post-workout (within 1–2 hours)
  Pairing a fuel oat bar with additional protein (for example, a shake from Marchon’s supplement range) can help cover both glycogen restoration and muscle repair, particularly after heavy or eccentric sessions.²⁷ ³⁰
  
  

Because MARCHON fuel bars use natural ingredients and avoid common gut irritants, they are suitable not only for serious gym-goers and runners, but also for health-conscious consumers who want natural energy bars that work in daily life as well as in the gym.

1. Wang Y, et al. Oat Beta-Glucan and Postprandial Blood Glucose Regulation: A Systematic Review and Meta-Analysis. Nutrients. 2020. (PMC7259015).
   
   

2. Tormási J, et al. Evaluation of protein quantity and protein nutritional quality of commercially available protein bars. 2025. (PMC11920265).
   
   

3. You XY, et al. Nutritional, Textural, and Sensory Attributes of Protein Bars with Mycoprotein. Foods. 2024. (PMC10930427).
   
   

4. Dordai L, et al. Simulated Gastrointestinal Digestion of Nutritive Raw Bars. Foods. 2023. (PMC10297024).
   
   

5. Ho HV, et al. The Effect of Oat β-Glucan on Postprandial Blood Glucose and Insulin Responses: A Systematic Review and Meta-analysis. Eur J Clin Nutr. 2021. (PMC8181916).
   
   

6. Wang Y, et al. Oat beta-glucans consumed at breakfast improve glucose responses later in the day. Food Funct. 2025. (linked via RSC).
   
   

7. Koenig RT, et al. Acute Effects of Oatmeal on Exercise-Induced Reactive Oxygen Species Production and Blood Glucose. Antioxidants. 2020. (PMC7822041).
   
   

8. Hsu YJ, et al. Supplementation with oat protein ameliorates exercise-induced fatigue. J Int Soc Sports Nutr. 2013. (PMID: 23147802).
   
   

9. Hwang H, et al. Effects of oat protein supplementation on skeletal muscle damage and recovery after eccentric exercise. 2018. (PMID: 30094437).
   
   

10. Jeukendrup AE. Carbohydrates and Endurance Exercise: A Narrative Review of a Food-First Approach. Nutrients. 2023. (PMC10054587).