Cardio, Strength Training and Protein: How They Fit Together

By Dr. Eugene Capitano, DC, MSc

You have probably heard three pieces of advice: do your cardio, lift weights, and eat enough protein. But how do they fit into the same routine?

I would start with a different question: what are you asking each one to do?

This is the practical companion to my two articles on Zone 2 training and metabolic flexibility. Those explain the exercise science. Here, we connect it to everyday training and food choices.

Different jobs, one routine

• Cardio develops your ability to sustain activity.
• Resistance training challenges your muscles to produce force.
• Protein supplies amino acids used in tissue repair and adaptation.

These are complementary jobs, not three versions of the same thing. A protein shake does not replace a training session, and a hard workout does not make food irrelevant.

Where Zone 2 fits

Zone 2 is one useful way to organise steady aerobic exercise. Over time, endurance training can increase the mitochondrial content of muscle—the machinery involved in producing usable energy.

That adaptation is not exclusive to Zone 2. A large research synthesis found improvements with continuous endurance training, high-intensity training and sprint intervals. There is more than one route to a fitter aerobic system. Mølmen and colleagues, 2025

For the fuller explanation, read Zone 2 Training: Why It Matters—Without Overthinking It.

Do cardio and strength training compete?

You do not generally have to choose between becoming fitter and becoming stronger.

A review of 43 studies found that combining aerobic and strength training did not significantly reduce gains in whole-muscle size or maximal strength compared with strength training alone. Explosive-strength gains were more vulnerable, particularly when both were done in the same session. That is a useful qualification—not a reason to abandon cardio. Schumann and colleagues, 2022

My practical starting point is to make room for both, then adjust the workload to your goals and recovery. Build from your current ability rather than copying someone else's hardest week.

Where protein fits—and where it does not

Resistance training provides a stimulus; dietary protein helps supply the material for adaptation. Across resistance-training trials, protein supplementation produced additional average gains in muscle mass and strength. That does not mean every person needs a supplement, or that more is always better. Morton and colleagues, 2018

Start with your daily intake, then consider how protein is distributed across meals. There is no need to treat the first few minutes after exercise as your only opportunity to eat. Whole foods can meet protein needs; a powder is a convenient option when it helps. Carbohydrate also has an important role in fuelling endurance exercise—protein does not replace it. Protein and exercise position stand

Think about your usual breakfast, lunch and dinner before adding a shake. Eggs, dairy, fish, meat, tofu and legumes can all contribute. Count the protein already in the meal, including milk or yogurt used in a shake. If food already meets your needs, an extra serving is not automatically necessary.

Turn the idea into a practical starting point

The TLC Precision Dosage Calculator estimates a daily protein range, a meal-level target and a serving of the selected TLC protein based on your inputs.

You can explore it before choosing or buying a product. Use the results to help plan your meals—not as a diagnosis or an instruction to add powder on top of an already adequate diet.

Explore the protein dosage calculator →

The calculator estimates protein intake. It does not measure your fitness, diagnose metabolic inflexibility or tell you how much fat you are burning.

Continue with the exercise science

Part 1: Zone 2 training—what it is and why it matters →

An approachable guide to steady aerobic training, without making every workout a heart-rate calculation.

Part 2: Metabolic flexibility—and where Zone 2 fits →

How the body adjusts its use of fat and carbohydrate, and why using more fat during a workout is not the same as losing more body fat.

If a protein powder would be useful in your routine, you can compare TLC's whey and plant proteins and read the ingredient and nutrition information before deciding. Choosing a powder is separate from choosing a training programme.

The takeaway

Build aerobic fitness. Train for strength. Eat to support the work.

That is how these pieces fit together: a sustainable routine, supported by food—not a single workout zone or a particular tub of protein.

Disclosure: I am a co-founder of TLC PureOrigin.

Author Information

Dr. Eugene Capitano, DC, MSc, is a chiropractor, rehabilitation clinician, and researcher with more than 25 years of clinical experience. He earned an MSc in Psychology & Neuroscience of Mental Health from King’s College London and holds the ACSM Exercise is Medicine® (EIM) Credential and the ACSM Certified Personal Trainer® (ACSM-CPT®) certification. His research interests include the gut–brain–muscle axis, microbiome-targeted nutrition, resistance training, mitochondrial function, metabolic health, and healthy aging.

Affiliation: TLC NeuroMicrobiome Labs Inc., Winnipeg, Manitoba, Canada

Medical and Nutritional Disclaimer

This information is provided for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Individuals must consult a qualified healthcare provider or registered dietitian before making significant changes to their diet or exercise regimen.

Important Safety Notice: Individuals with pre-existing renal impairment, diabetes, or other chronic metabolic conditions should consult a healthcare provider before significantly increasing protein intake. Higher-end protein intakes should be used only under medical supervision, with regular monitoring of renal function.