Cardio, Aerobics, and Fat Loss Part 1
To do cardio, or to not do cardio. A great tool for healthy fat loss, or a waste of time? Depending on who is on the podcast mic, most people will say that cardio is not necessary to lose fat, and all people need to do is just walk 10k steps, eat within their “macros” and above all else, maintain a CaLoRiE dEfiCiT. While this works for many, does it work for most people? And does it actually work long term for most people?
In our last article we discussed intuitive eating, how it is the best way to create a healthy environment within the body, and how it is the best way to build a foundation that promotes healthy fat loss over time. While intuitive eating is not a fat loss tool, aerobics/exercise is, if not the best tool, despite what fitness gurus will tell you, and I shall explain my case for aerobic exercise.
Before diving into the benefits of aerobic exercise, let’s look at the recommended physical activity guidelines. While I’m not the biggest fan of the CDC, their recommendations of 150 to 300 minutes of aerobic activity per week are widely accepted by professionals and institutions.
For general health, 150 minutes is the minimum, while for noticeable improvements in fat loss and body composition, closer to 300–420 minutes per week is ideal.
Why such high numbers? Because adaptation requires time under stimulus. Just like you won’t get stronger without sufficient strength training, your metabolism and cardiovascular system won’t improve without enough aerobic work.
The body adapts to what it’s consistently exposed to—not what we think it should respond to. And the primary goal is to improve your metabolic (and cardiovascular as a byproduct) system, not to burn calories (yes you read that correctly)
At rest and during low-intensity activity, the body mainly runs on fat. But to boost fat oxidation (breaking it down to use for energy) and improve metabolic health, you need to give it a reason: consistent aerobic activity at sufficient volume.
That’s what triggers the structural and hormonal changes needed to handle that new demand.
Yes, an hour a day might sound like a lot to an adult, but to a kid, it’s just called play. Perspective matters. The body doesn't care how busy you are. It only responds to what you give it or don't give it. This is not to discount responsibilities people have, especially if they are working parents.
It’s to remind you that your biology doesn’t operate on excuses or intentions — it responds to input, demand, and consistency. That might sound harsh, but it’s actually empowering. Because once you understand that your health is a system of cause and effect, you can start looking for ways to work with your body rather than against it.
Even small, consistent changes like 20 minutes a day, can compound and can then potentially improve to 30 min a day, or 40 and so on. The point isn’t to be perfect, it is to build momentum and stay consistent to develop the adaptations and results we are looking for.
Now once the adaptations begin to develop from consistent aerobic training, multiple things will be improved:
First, fat oxidation efficiency (the body’s ability to use fat for energy) improves. This matters because the better your body is at burning fat, the less it relies on sugar (glucose). As a result, it helps preserve muscle, enhances endurance (making aerobic training easier and more enjoyable), and supports sustainable fat loss over time.
You don’t necessarily need to be in a calorie deficit to lose fat — technically, you need to be in a fat deficit. More on that later.
Frequent and consistent aerobic exercise improves insulin sensitivity, which lowers baseline insulin levels and makes it easier for the body to mobilize and burn fat. When insulin levels are high, the body prioritizes managing blood sugar over burning fat, making fat loss more difficult.
As insulin sensitivity improves, mitochondrial capacity also increases, allowing the body to store and use energy more efficiently with less insulin. This shifts the body toward using more fat for energy, rather than relying primarily on glucose or frequent food intake.
This leads to another key benefit of improved metabolic health through aerobic exercise: better appetite regulation. Most fitness influencers, trainers, and nutritionists tend to focus on suppressing appetite to force a calorie deficit and drive fat loss. But this approach is often inefficient, unpleasant, and can have serious physiological downsides.
A better strategy is to regulate and stabilize appetite so the body naturally gets the energy and nutrients it needs to function optimally and build a more robust metabolism. Rather than forcing fat loss, you’re supporting the very systems that drive it—leading to more sustainable, natural fat loss that’s actually maintainable over time.
Appetite is regulated by a complex interplay of hormones. Chronically elevated cortisol—whether from stress, undereating, or overtraining (especially when intense exercise is paired with inadequate fuel and rest)—can disrupt hunger signals. This often leads to blunted appetite at some times, followed by intense cravings at others, creating a dysregulated pattern over days and weeks.
Consistent low-intensity aerobic exercise helps lower and stabilize baseline cortisol levels over time, which is especially important for women. Lower cortisol means more predictable hunger patterns and fewer stress-driven cravings.
Building on this, key appetite hormones like ghrelin (which signals hunger) and leptin (which signals fullness) also become more sensitive and better regulated through consistent aerobic exercise. In metabolically stressed bodies—especially after years of dieting or food control—these signals can become blunted or confused.
Some people rarely feel true hunger, while others feel constantly hungry even when full, a sign of leptin resistance. Often, both patterns can cycle over time.
Aerobic training, especially when combined with intuitive eating, helps restore hormone sensitivity, making it easier to trust internal hunger cues and eat without obsessively tracking or restricting.
Aerobic exercise is one of the most powerful and natural regulators of daily mood and energy. Unlike stimulants or quick fixes, it rebuilds the body’s internal systems—helping you feel better and more energized with less effort over time.
It stabilizes blood sugar by improving insulin sensitivity, lowers baseline cortisol, boosts mood by increasing serotonin, dopamine, and endorphins, and strengthens parasympathetic tone. Together, these adaptations improve the body's internal environment, making it more efficient at using and burning fat.
This supports long-term fat loss while also creating a more resilient and sustainable foundation for health.
To continue, proceed to part 2.
TL;DR:
Main Premise
Cardio is often dismissed in fitness circles as unnecessary for fat loss.
However, aerobic exercise is arguably the best tool for sustainable, healthy fat loss.
The Case for Cardio
Intuitive eating builds a healthy foundation but aerobic training drives fat loss.
The CDC recommends 150–300+ minutes/week of aerobic activity for health and fat loss.
Higher volume is needed for metabolic adaptations, not just calorie burning.
Why It Works
The body adapts to consistent stimulus, not intention.
Fat is the primary fuel at rest and during low-intensity activity.
Aerobic work increases fat oxidation capacity and metabolic efficiency.
Adaptations from Cardio
Improved fat oxidation: Burn more fat, preserve muscle, enhance endurance.
Better insulin sensitivity: Lower insulin levels make fat more accessible for energy.
Increased mitochondrial function: Energy is stored/used more efficiently.
Appetite regulation: More stable hunger/fullness cues via better hormone balance.
Hormonal Impact
Lower baseline cortisol: Reduces stress-driven eating.
Balanced ghrelin and leptin: Hunger/fullness signals become clearer and more accurate.
Supports recovery from metabolic stress caused by chronic dieting or restriction.
Mental & Emotional Benefits
Aerobic training naturally improves mood and energy over time.
Boosts serotonin, dopamine, endorphins, and parasympathetic tone.
Helps stabilize blood sugar, lower stress, and improve overall well-being.
Conclusion
You don’t need perfection—just consistency.
Even 20 minutes a day can snowball into major results.
Aerobic exercise builds a resilient, efficient, and fat-burning system that supports long-term health and fat loss.
