Is Fasting Good for Fat Loss?

“Isn’t fasting just starving yourself?”

“But what about autophagy?”

“Do I have to skip breakfast to lose weight?”

If you’ve ever typed "is fasting good for fat loss" into Google—or asked your personal trainer while trying to keep your stomach from growling—you’re not alone. Fasting has exploded in popularity. But does it actually help you lose fat? Or is it just another overhyped trend?

As a coach offering personal training in Bristol, I hear about fasting a lot—from curiosity to confusion. So let’s break it all down.

🍽️ What Is Fasting, Anyway?

Think of your body like a hybrid car. When you eat, it's running on fresh fuel—glucose from your last meal. When you don’t eat for a while, the system gradually switches to battery mode—using stored fat and glycogen.

At its simplest, fasting is just choosing not to eat for a period of time. This can range from:

  • Intermittent fasting (IF) – like 16:8, where you fast for 16 hours and eat within an 8-hour window

  • Alternate-day fasting – eating one day, fasting (or eating very little) the next

  • Extended fasts – 24 hours or longer

Think of fasting as pressing pause on your food intake. Just like you might schedule time off from work to reset, fasting is a break from digestion. The idea is that by limiting when you eat, you'll naturally eat less—and lose weight.

🧪 So… Does Fasting Help With Fat Loss?

Yes—but not for the reason many people think.

A 2015 systematic review in Obesity Reviews found that intermittent fasting can produce weight loss comparable to traditional calorie-restricted diets, as long as people stuck to it [1].

And a 2020 randomized controlled trial in JAMA Internal Medicine found no significant difference in fat lossbetween people following intermittent fasting and those eating regularly—when calories were matched [2].

💬 Bottom line? Fasting can help you eat fewer calories—but it’s not superior to any other method if calories are equal.

🧠 Fasting: Is It Really Magic?

😤 Why It’s Not Magic

Here’s where things often get misunderstood. People start fasting, lose weight, and credit the fasting itself.

But often, it’s just because:

  • They skip a meal (hello, fewer calories)

  • They avoid evening snacking

  • They become more mindful of what they eat

It’s like switching from cash to card and thinking your spending habits changed because of the bank. No—you just see the numbers more clearly now.

The TREAT trial, published in JAMA Internal Medicine, compared people who ate normally vs those who followed a strict 16:8 fasting plan. The result?

No significant difference in fat loss between the groups [2].


🧠 Why Fasting COULD Be Helpful

Some people find fasting helps them feel more in control of their eating. Less time spent eating can mean:

  • Fewer meals to plan

  • Fewer chances to snack

  • Less decision fatigue

Imagine it like putting your meals on airplane mode: fewer distractions, more structure.

Some studies support this. For example:

  • A 2020 systematic review in Canadian Family Physician found intermittent fasting can be as effective as daily calorie restriction for weight loss—if people stick to it [3].

  • A 2015 paper in Obesity noted that time-restricted eating (like 16:8) may improve insulin sensitivity and appetite regulation [4].

So yes—it can help. Especially if it simplifies your day and helps you avoid high-calorie snacking.


😵‍💫 When Fasting Doesn’t Work

Just like any tool, fasting has its downsides:

  • Some people binge when they finally break their fast

  • It can mess with training sessions (especially morning workouts)

  • It may worsen food obsession or trigger disordered eating patterns

  • It’s not suitable for everyone (especially those with medical conditions, underweight individuals, or pregnant women)

Think of fasting like a pair of running shoes. They help you go far—but only if they fit your feet.


🤔 So… Should You Fast?

Here’s your litmus test:

❓ Do you feel better eating fewer meals?

❓ Can you fast without obsessing over food?

❓ Does it help you control your intake and simplify your day?

If yes—fasting might be a great fit.

But if it leaves you:

  • Dreaming of croissants at 10am

  • Snapping at your partner over toast

  • Caving and over-eating later…

…then maybe not.


🧠 Final Thought

Fasting is a tool, not a rule.

It’s not better than other diets—it’s just a structure that works well for some people. Like any eating approach, it only helps with fat loss if it leads to a calorie deficit that you can maintain over time.

✏️ It’s not about when you eat—it’s about how much and what you eat overall.

So if skipping breakfast helps? Go for it.

If it ruins your morning mood? Don’t force it.


🎥 Prefer to Watch or Listen?

💪 Need Help Finding What Works For You?

If you're sick of jumping between diets, feeling confused about carbs, or wondering how to balance eating and exercise, our personal training team in Bristol is here to help.

We’ll help you build habits that last—without starving, stressing, or second-guessing yourself.

👉 Book a Free Consultation



📚 References

  1. Seimon RV, Roekenes JA, Zibellini J, et al. Intermittent fasting combined with calorie restriction is effective for weight loss: A systematic review and meta-analysis. Obesity Reviews. 2015;16(7): 613–624.

  2. Lowe DA, Wu N, Rohdin-Bibby L, et al. Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity: The TREAT Randomized Clinical Trial. JAMA Internal Medicine. 2020;180(11):1491–1499.

  3. Patterson RE, Sears DD. Metabolic effects of intermittent fasting. Canadian Family Physician. 2017;63(8): 511–517.

  4. Sutton EF, Beyl R, Early KS, et al. Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even Without Weight Loss in Men with Prediabetes. Obesity. 2018;26(5): 852–860.

Danny Harris