Juicebox Podcast: Type 1 Diabetes

Episode #1440: Fox in the Loop House: Part 5
Host: Scott Benner
Guest: Kenny Fox
Date: February 21, 2025

Episode Overview

This episode continues the deep dive into practical, real-world strategies for managing type 1 diabetes—specifically using the Loop automated insulin delivery system. Host Scott Benner and recurring guest Kenny Fox unpack meal management, carb ratios, handling fat and protein, carb entry adjustments, and pattern recognition within Loop. The discussion blends nuanced Loop mechanics with broad, accessible diabetes management principles, aiming to empower listeners to be "Bold with Insulin" and develop a deeper, systems-level understanding of diabetes.

Key Discussion Points & Insights

1. How Loop Handles Different Foods and Meal Types

• Universal Principles:
  • Kenny emphasizes that the techniques and principles he discusses apply to all diets—low-carb, American standard, vegan, etc.
    • “People that eat low carb do struggle a little bit and may have to do a couple little tweaks. But generally the rules… will apply to anyone eating anything.” [03:11 – Kenny]
• Carb Entry Timing:
  • Loop uses meal "duration" categories: fast, medium, or slow (represented by emojis like lollipop, taco, pizza).
  • Loop initially expects the same blood sugar response no matter what carb window is chosen; it’s up to the user to pick the correct duration for the food, especially higher fat/protein meals.
    • “Loop models all meals the same to a degree… you get to tell it if it’s a fast, a medium or a slow meal and it’s going to fit the entire expected carb impact… inside basically a, a short, a medium and a long amount of time.” [04:14 – Kenny]

2. Practical Management at School

• Real-life Workflow:
  • Kenny’s daughter takes a picture of her meal at school, sends it to him, then they discuss carb counts and entry duration (often using longer windows for fatty cafeteria foods).
    • Physical activity before/after lunch influences their dosing (less need to pre-bolus due to PE mitigating glucose spikes).
    • Loop’s ability to edit previous carb entries is helpful for variable school meals and unpredictable appetites.
    • “She’ll send me a picture, a text at lunchtime, and then… she knows most of the meals, and she’ll enter them… By now… she’s getting it right most of the time now.” [07:37 – Kenny]

3. Loop’s Dynamic Carb Absorption Model

• How Insulin/Carb Balance is Tracked:
  • Loop continuously subtracts “active carbs” as blood sugar rises, balances with “insulin on board (IOB)” to generate predictions.
  • Correct meal modeling depends on having settings (carb ratio, ISF) properly tuned.
    • “It uses what’s called dynamic carb absorption… It’s tracking both the insulin on board as well as the carbs on board.” [10:50 – Kenny]
• Windowing & Timing:
  • Duration settings and their “safety extension” (Loop adds 50% to the entered absorption time as a buffer).
    • “Loop says great, I hear you on the like three hours, let’s say. But just in case you’re wrong, …I’m going to add 50%…” [38:04 – Kenny]

4. Detecting and Addressing Highs Post-Meal

• Analyzing Meal Outcomes:
  • Steps: check overnight basals, review confidence in food bolus, double-check carb counts, consider fat/protein, review absorption settings, then sensitivity factors last.
    • “If you’re in the middle of a meal, you might want to look at the prediction… But the initial gut reaction is if you think you need more insulin, and you’re generally pretty good at guessing… just give it, and then we’ll figure out how to tweak loop later.” [22:09 – Kenny]
• Highs and Counting Errors:
  • With a rise above 160 mg/dL, Scott and Kenny typically double-check carb counts or pre-bolus timing.
    • “If it’s a home cooked… meal and we’re getting to 160, that’s a little unusual even at the beginning… then we’ll let it go.” [26:17 – Kenny]

5. The Role of Fat and Protein in Meal Bolusing

• Fat/Protein Calculation:
  • Kenny’s simplified approach: add together grams of fat + protein, then divide by three to estimate carb equivalent for insulin dosing (especially useful for restaurant/“pizza” meals).
    • “What we do for fat and protein… is we’ll do the fat grams and the protein grams, add them together, and then just divide it by three.” [31:54 – Kenny]
• Entry Methods:
  • Detailed: Separate entries for actual carbs, fat/protein, each with their own durations.
  • Practical: One entry combining carbs + 1/3 fat/protein as long duration (“pizza” icon, 5 hour).
  • Tessa: Often uses just one entry now as older kid with higher insulin needs and better tolerance for overlaps.

6. Nighttime Rises and Circadian Rhythm

• Problem:
  • Meals eaten at night can result in unexpected post-bedtime blood sugar rises.
• Solution:
  • Kenny learned that longer meal absorption windows (e.g., “pizza” instead of “taco” or extending hours) at dinner more accurately reflect slower digestion/storage at night due to circadian rhythms, reducing lows before bed and prepping Loop to handle later rises.
    • “If you use a medium taco at lunch, try the pizza one… at dinner… get less insulin up front, helps mitigate the lows… and it has a lot of active carbs left for when the rise does show up.” [47:02 – Kenny]

7. Nuanced Carb Counting and Behavioral Habits

• Don’t Routinely Enter “Fake” Carbs:
  • While adjusting entries ad-hoc may help in the moment, it defeats the purpose of using data for long-term adjustment.
    • “If you really want to use the system and the data to make a decision, you’ll eventually need to go back and fix those… That’s something to pay attention to. I see a habit people develop.” [44:40 – Kenny]
• Using School Nutrition Data:
  • Tessa’s school provides nutrition info online, but Kenny treats it only as a starting estimate.

8. Broad Lessons: Beyond Loop, Into Physiology

• Diabetes management is about understanding body rhythms, food absorption, and the harmony (or lack thereof) with insulin—not just the mechanics of a system like Loop.
  • “As much as this conversation is about how loop works… it’s really just as much, if not more, about how your body works, how it interacts with the food and your exercise… the loop is almost inconsequential in the conversation… Does that make sense?” [52:32 – Scott]
  • “That’s exactly right… It can feel technical, but once you wrap your head around it, it’s something you can adjust to pretty well.” [53:09 – Kenny]

Notable Quotes & Memorable Moments

Food and Loop

• “Loop’s worried about is that you don’t go low, and it’s going to treat every meal initially the same.” [04:14 – Kenny]
• “You can spend a lot of time fiddling with, editing carb entries when you’re guessing because a lot of our entries are guesses.” [08:15 – Kenny]

Highs and Counting

• “If it’s a more balanced meal and you see that rise like that, then your expectation is we miscounted the carbs. That’s right.” [27:36 – Scott]
• Scott: “Did you just eat a bag of sugar? …Was it two bags of sugar?” [26:56 – Scott]

Fat/Protein Management

• “We’ll do the fat grams and the protein grams, add them together, and then just divide it by three…” [31:54 – Kenny]
• “So those are the two methods we use. I would say we use one entry a lot... if she starts to get a little bit high, like four or five hours after the meal… then we’ll go ahead… add a few more carbs later… as a second entry after the fact.” [35:09 – Kenny]

Nighttime Rises

• “When we eat in the morning, our body will… digest the food, convert all of it right now… As we get closer to sleeping time… a portion of the food… starts to be stored as fat for consumption later. And I feel like that hit me was like, oh, that explains why if we have the same food at lunch as we do at dinner…the spike isn’t as strong at dinner…” [47:02 – Kenny]

Broader Philosophy

• “There is a way to have the same results that you’re seeing with other people all the time. It’s the basis for the podcast for My Money… Kenny’s not a special person… you don’t need to understand it as well as Kenny does to have the results that Kenny’s having with his daughter.” [54:18 – Scott]

Important Timestamps

• [03:11] – Universal carb handling & diet flexibility
• [07:37] – Practical school lunch workflow & texting for carb counting
• [10:50] – How Loop tracks and subtracts active carbs (dynamic carb absorption)
• [22:09] – Detailed steps for analyzing and managing post-meal highs
• [31:54] – Simple formula for calculating fat/protein equivalent for insulin
• [38:04] – How Loop extends meal absorption windows (safety buffer)
• [47:02] – Using circadian rhythm (meal timing) to tweak Loop entries for nighttime rises
• [52:32] – Scott recaps the philosophy: diabetes management is more than just Loop mechanics

Final Lessons

• Pay close attention to how Loop “sees” your entries and how your body digests various foods.
• Adjust meal entry times and add future entries, especially for high-fat/protein meals.
• Avoid masking mistakes with frequent “fake” carb entries; instead, review and tweak your ratios/settings.
• Nighttime rises have a physiological (circadian) underpinning—use longer absorption times at dinner.
• Your approach may not need to be perfect or mathematical to achieve great results; understanding core patterns, mechanisms, and regular review leads to confidence and success.

For more information and educational resources, visit Fox in the Loop House and listen to other episodes of the Juicebox Podcast, especially the Bold Beginnings and Pro Tip series.