What Came Back After My 7-Day Water Fast? (Fat, Muscle, or Just Water)

So I didn’t eat for 7 days… and then I started eating again.

What came back? Fat? Muscle? Water weight? My appetite for croissants? Let’s break it all down. And trust me, the numbers are more interesting than you’d think.

💥 Quick Recap: What I Lost During the Fast

In my last post, I walked you through my 7-day water fast. Over that week, I dropped 11.6 pounds (5.3 kg). That included:

  • Fat mass: down 4.6 pounds (2.1 kg)

  • Lean tissue: down 7.1 pounds (3.2 kg)

Now it’s time to talk about what came back during the refeed.

🍽️ The Refeed Week: What Happened

I started eating again on Day 8. I kept it clean and simple: small portions, cruciferous veggies, soups, probiotics, and no junk. My digestion handled it like a champ. No bloating, no cramps, no bathroom emergencies.

By the end of the refeed week, I was back up to 157.2 pounds (71.3 kg). That’s a gain of 6.7 pounds (3 kg). But here’s the thing: most of that weight isn’t fat.

  • Fat: went from 16.8 to 17.3 lbs (+0.5 lbs / 0.2 kg)

  • Lean tissue: went from 126.5 to 132.8 lbs (+6.3 lbs / 2.9 kg)

  • Bone mass: steady at ~7.0 lbs (DEXA scan noise likely)

In short: most of the fat loss stayed off. Lean mass (mostly water and glycogen) bounced back fast. This is a good thing.

🔬 Metabolic Markers: Back to Sugar Mode

Ketones started Day 8 at 4.8 mmol/L but dropped fast:

  • 3.1 → 1.1 → 1.4 →0.8 → 0.6 mmol/L

  • Why? Carbs and insulin turned ketone production off. Totally normal.

Glucose told the same story:

  • Day 7 ended at 68 mg/dL

  • Post-refeed peak: 134 mg/dL (thanks, carrot juice...)

  • Then it gradually dropped to mid-90s

GKI (Glucose-Ketone Index):

  • During fast: < 1 (deep ketosis)

  • After refeed: spiked to 20.9, then stabilized around 15

So yes, ketosis ended quickly, but that’s expected. It’s a flexible metabolic state, not a permanent one.

💓 Recovery Markers: Did My Body Bounce Back?

HRV (Heart Rate Variability):

  • During fast: dropped as low as 18 ms

  • Post-refeed: bounced back to 50–54 ms

Resting Heart Rate (RHR):

  • During fast: increased

  • After refeed: dropped to 43–45 bpmlower than before the fast

Sleep Score:

  • During fast: rough, low 60s

  • After refeed: much better, some nights hit 80+

Respiratory Rate:

  • Normalized quickly, back to ~12.9/min

🧪 Tools I Used to Track the Journey

If you're curious about tracking your own fasts, here’s what I used:

🛒 Full gear list

📺 Watch the Full Video

If you haven’t seen the video yet — it breaks this all down with charts, graphs, and a bit of humor.

👉 Watch “What Came Back After My 7-Day Fast” on YouTube

✅ Final Takeaways

  • Weight came back, but mostly water and glycogen

  • Fat gain? Just 0.5 lbs

  • Muscle? Rehydrated and already recovering

  • Digestion? Smooth

  • Sleep and HRV? Improved

  • Energy? Better than before

Would I do it again? Absolutely. But next time I’ll add strength training sooner to preserve lean mass.

Like this post? Check out the tools I used, subscribe for more health experiments, and stay tuned for what’s next on Practical Health.

Previous
Previous

🏃‍♂️ How to Choose the Best Running Shoes (Without Losing Your Mind)

Next
Next

How to Wake Up Fast: 7 Science-Backed Tricks That Actually Work