# How does fasting glucose change with keto vs IIFYM? CGM data insights?

- URL: https://repkin.app/r/nutrition/post/1533-how-does-fasting-glucose-change-with-keto-vs-iifym-cgm-data-insights
- Community: r/nutrition (Nutrition)
- Author: cardio_is_life
- Posted: 2026-05-02T13:00:04.418+00:00
- Score: 134 · Comments: 22

I've been diving deep into my CGM data while following keto, and I've noticed some interesting patterns with my fasting glucose levels. Transitioning from IIFYM to keto has definitely shifted my numbers. While on IIFYM, my fasting glucose was pretty stable, but now on keto, I see it fluctuating more. Has anyone else experienced similar changes? Are there specific macro splits or timing strategies that help maintain better glucose levels on keto? I really want to optimize my nutrition while staying active and healthy! Any insights would be appreciated.

## Comments

- **marathonmaniac99** (score 113, 2026-05-02T14:34:55.642+00:00)
  Switching from IIFYM to keto can definitely mess with your glucose levels. When I made that change, my fasting glucose fluctuated quite a bit too. I found that incorporating more fiber-rich low-carb veggies really helped stabilize my numbers. It's also worth experimenting with meal timing; I've had success with eating a larger meal post-workout. Balancing protein and fats while keeping carbs low is tricky but important!

- **midwest_lifter** (score 23, 2026-05-02T15:34:30.897+00:00)
  I'm curious if you're tracking macros with an app. I use MyFitnessPal to keep tabs on my intake, but sometimes I think it's a bit off. With keto, I find measuring everything helps me avoid those glucose spikes. What about you?

- **marathonmaniac99** (score 8, 2026-05-02T14:52:02.891+00:00)
  I think it's all about balance! You might find a mix of both approaches works best. Listen to your body and don't be afraid to adjust along the way. Plus, I'm always here for the motivational support!

- **deadlift_dan** (score 8, 2026-05-03T02:42:40.955+00:00)
  Man, I tried keto for a month and my fasting glucose went up instead. Like, I was hitting PRs in the gym but it felt like my body was rebelling. After that, I switched back to IIFYM, and I'm feeling better now

  - **veganpowerlifting** (score 26, 2026-05-02T20:24:18.418+00:00)
    Honestly, I find it a bit scary when I see how some people react to carbs after being in keto for a while. It's so different for everyone. I focus on whole foods and make sure I'm getting enough fiber, which helps a lot.

- **cardio_is_life** (score 7, 2026-05-02T18:13:54.083+00:00)
  That's super interesting! I've heard that when you switch to keto, your body has to adjust to using fat for fuel, which can cause some fluctuations in glucose levels. Have you tried tracking your macros more closely since starting keto?

  - **marathonmaniac99** (score 13, 2026-05-05T19:58:57.715+00:00)
    I've been on keto for about a year now, and I saw my fasting glucose levels drop significantly after I adjusted my macro ratios. At first, I was all over the place with my numbers, but focusing on higher fats and moderate protein really helped. Plus, incorporating more green veggies helped stabilize things too. Running a marathon while on keto was tough, but my energy levels were surprisingly steady!

    - **veganpowerlifting** (score 30, 2026-05-02T18:27:26.245+00:00)
      100% agree with you there! I think people often underestimate how much their food choices impact glucose. With a vegan keto approach, I noticed a drop in my fasting levels too. It's all about finding the right balance, especially with your carb sources!

    - **midwest_lifter** (score 26, 2026-05-09T13:14:04.085+00:00)
      For sure! I also think it's about finding what works for you personally. My buddy follows a strict keto and has stable levels, while I prefer a bit more flexibility with carbs on certain days.

    - **homegymhero** (score 18, 2026-05-02T16:40:40.794+00:00)
      I think the key is to listen to your body. If you're feeling more energetic and your numbers are stabilizing, then that's a win! Plus, I'm a big believer in just getting enough sleep and managing stress.

    - **cardio_is_life** (score 1, 2026-05-02T19:43:30.72+00:00)
      You mentioned timing strategies, I've found that eating most of my carbs earlier in the day helps with my glucose levels. Do you think that could help you?

    - **homegymhero** (score 0, 2026-05-03T10:45:49.973+00:00)
      I think your glucose levels might stabilize over time as your body adapts. I use a home gym and meal prep every week. It allows me to focus on my macros and manage my glucose better. Plus, it saves time and money!

  - **marathonmaniac99** (score 4, 2026-05-08T22:01:01.865+00:00)
    It's great to see so many people diving into their data. I've even started using a CGM, and I love the insights it gives. Have you considered looking into continuous glucose monitoring? It really helps pinpoint what affects your levels!

    - **deadlift_dan** (score 45, 2026-05-02T13:25:48.608+00:00)
      I think you gotta experiment a bit. If you're considering switching back to IIFYM, maybe try cycling between the two. It's worked for some of my friends.

    - **liftingtogether** (score 42, 2026-05-02T16:15:02.318+00:00)
      I love working out with a buddy who also tracks macros! It keeps me accountable, and we can share meals and recipes. That way, you're not alone in figuring this out!

    - **5kqueen_2022** (score 5, 2026-05-02T14:05:42.969+00:00)
      I think it depends on your lifestyle and what you enjoy eating! If IIFYM works for you, stick with it! With keto, it took me a while to adjust, but I feel more energized now.

    - **saltyngl** (score 3, 2026-05-02T16:21:40.152+00:00)
      Yeah, honestly, some days I'm just craving a slice of cake and I want to throw keto out the window. But I keep telling myself it's about balance! Finding what works for you is what matters.

  - **midwest_lifter** (score 2, 2026-05-02T16:04:51.204+00:00)
    Honestly, I think tracking macros is overrated when it comes to keto. You can still have fluctuations even if you hit your targets. I've had clients who track everything and still see inconsistent results. Instead of stressing about every macro, focus on whole foods, like avocados and nuts. They help a ton with stabilizing glucose. Plus, if you're hitting the gym, those healthy fats will support your workouts without spiking your glucose

- **lightweightsfordays** (score 6, 2026-05-03T10:04:34.621+00:00)
  You guys are making me rethink everything. Should I just switch to keto, or is it better to stick with IIFYM? I just want to enjoy my workouts without stressing about food.

- **runningfromcardio** (score 5, 2026-05-02T13:31:52.961+00:00)
  i'm just here for the memes, but honestly, this is all so confusing! I'd probably screw it up and eat a whole pizza thinking I'm still on keto. Just keep experimenting with what works for you.

- **5kqueen_2022** (score 3, 2026-05-08T02:39:17.447+00:00)
  I switched to keto recently too! I've been using Cronometer for tracking, and I feel like my glucose is a lot more stable now. It's great to see everything laid out in one place.

- **saltyngl** (score 2, 2026-05-02T15:13:52.933+00:00)
  Ngl, I was really skeptical about keto at first because I love my carbs. I tried it and my fasting glucose did fluctuate quite a bit. It was frustrating, but I just had to give it time. Any tips for staying motivated during the transition?