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Understanding the Impact of Energy Deficits on Resistance Training Outcomes

When it comes to increasing performance and reduction of injury, we should start to look at nuances regarding resistance training and why your athlete may not be getting the gains you think they should.

When it comes to resistance training (RT), the role of energy intake is crucial for achieving the desired gains in muscle mass and strength. While it’s well-documented that short-term energy deficits can negatively impact anabolic hormones and muscle protein synthesis, the long-term effects of sustained energy shortages during resistance training are less understood. A new study delves into these effects, offering valuable insights for anyone engaged in resistance training, especially those looking to optimize their training results in the face of dietary restrictions.

In our recent Podcast with Registered Dietician Wes Bressell, we discussed the role of hydration and it's key role in fascia and injury prevention. In this study we are taking on calorie deficits and why parents need to consider nuances in strength gains.

In an effort to understand how prolonged energy deficits affect resistance training outcomes, researchers conducted a systematic review, sourcing data from PubMed and SportDiscus. This review focused on randomized controlled trials that investigated the outcomes of resistance training under conditions of energy deficit (RT+ED) for three weeks or more.

Research Design and Methods:

The researchers organized the study data into two primary analyses:

Analysis A: This involved a meta-analysis comparing the outcomes between groups performing resistance training in an energy deficit (RT+ED) and those in a control group with no energy deficit (RT+CON).

Analysis B: This consisted of a qualitative comparison, matching studies of RT+ED with separate RT+CON studies based on participant characteristics and the nature of interventions.

Key Findings:

Lean Mass Gains: In Analysis A, the meta-analysis revealed that lean mass (LM) gains were significantly impaired in the RT+ED group compared to the RT+CON group (effect size (ES) = -0.57, p = 0.02). Analysis B supported this finding, showing further impairment in LM gains for RT+ED versus RT+CON (ES: -0.11, p = 0.03).

Strength Gains: Interestingly, the strength gains were not significantly different between the RT+ED and RT+CON groups in Analysis A (ES = -0.31, p = 0.28). Similarly, Analysis B showed comparable strength gains between RT+ED and RT+CON (RT+ED ES: 0.84; RT+CON ES: 0.81).

Meta-Regression Insights: The pooled data from Analyses A and B in a meta-regression highlighted that an energy deficit of approximately 500 kcal per day was sufficient to prevent gains in lean mass.

Practical Implications:

These findings underscore a crucial point for fitness enthusiasts and athletes alike: while maintaining strength levels is possible, building or preserving lean mass under conditions of significant energy deficit poses a considerable challenge.

For Muscle Gain: Individuals targeting muscle mass increases should avoid prolonged periods of significant calorie deficits.

For Weight Management: Those aiming to preserve muscle mass during weight loss should limit their daily calorie deficit to no more than 500 kcal. This deficit should come from both movement and caloric.

Why is this information important?

As parents we tend to lean into more is better. The reality is like everything else there's a balance of what is needed for optimal performance. Stop comparing your time in athletics to now...

Fueling Performance:

Balanced Meals: Encourage a diet that includes a balance of carbohydrates, proteins, and fats. Carbohydrates are the main fuel source during high-intensity activities, proteins are crucial for muscle repair and growth, and fats provide necessary calories and support cell function.

Hydration: Keeping hydrated is crucial for performance and health. Water regulates body temperature, lubricates joints, and helps transport nutrients to give energy and keep athletes healthy. Parents should encourage drinking water before, during, and after sports activities.


Sufficient Sleep: Ensure athletes get enough sleep, which is crucial for recovery, cognitive function, and physical health. Teen athletes might need 8-10 hours of sleep per night.

Consistent Sleep Schedules: Encourage a regular sleep schedule to help regulate their body clock, which improves the quality of sleep.

Rest Days:

Scheduled Rest: Incorporate regular rest days to prevent overtraining. Rest days are critical for muscle recovery and help prevent injuries.

Active Recovery: Gentle, restorative activities like walking, yoga, or light swimming on rest days can aid muscle recovery and keep the body active without overexertion.

Summer is a fantastic time to address and reset these key components.

If you're in Jacksonville and looking for a comprehensive sports performance camp, we are offering two great locations to choose from!


Murphy C, Koehler K. Energy deficiency impairs resistance training gains in lean mass but not strength: A meta-analysis and meta-regression. Scand J Med Sci Sports. 2022 Jan;32(1):125-137. doi: 10.1111/sms.14075. Epub 2021 Oct 13. PMID: 34623696.

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