Podcast Summary: Short Wave – “Who Should Track Their Blood Sugar?”

Date: December 1, 2025
Host: Emily Kwong
Guest: Ping Huang (NPR Health Correspondent), Dr. Sarah Kim (Diabetologist, UCSF)

Episode Overview

The episode explores the growing accessibility of continuous glucose monitors (CGMs) and examines who should use them, especially given the rising prevalence of prediabetes and diabetes in the US. Host Emily Kwong is joined by health correspondent Ping Huang, who shares her personal experience using a CGM. The episode also features expert insights from Dr. Sarah Kim, a diabetologist at UCSF, who breaks down the science of glucose, insulin, and effective blood sugar management.

Key Discussion Points & Insights

The Prevalence of Prediabetes and CGM Accessibility

• Prediabetes is Widespread

  • Emily notes that about 1 in 3 US adults are prediabetic, often without realizing it. (02:12)
  • Ping Huang shares that she’s been prediabetic “on and off, and most recently it’s been mostly on.” (02:00)

• Continuous Glucose Monitors (CGMs) Go Over-the-Counter

  • Ping decided to try a CGM after they became available OTC, describing it as a small device on her arm, feeding her data via an app. (03:37)
  • CGMs track glucose via the interstitial fluid—not directly from the blood, but the readings closely reflect blood glucose. (03:13)

How CGMs Help with Blood Sugar Management

• Immediate Feedback Enables Lifestyle Tweaks

  • Ping observes significant blood sugar spikes after carb-heavy meals and prolonged periods of inactivity:

    “If I eat a sandwich for lunch, it’s going to really spike my blood sugar.” (04:22)

  • She sees real-time decline in blood glucose after walks:

    “It is also really helpful for me to take walks after meals, like just for 10 or 15 minutes. And I can actually see the impact of that immediately on... the graph that’s attached to my phone.” (04:22)

  • The device prompted Ping to exercise more, which has “made a big difference.” (04:22)

• Expert Affirmation

  • Dr. Sarah Kim:

    “You may see higher glucose rises after certain meals... you will see more variety in the glucose levels.” (02:31)

Glucose: The Science Behind Blood Sugar

• Role of Glucose

  • Dr. Kim explains:

    “Glucose comes from carbohydrates specifically, and sugars. And glucose is the specific kind of sugar that the body uses for energy currency. So we absolutely need glucose all the time to fuel our cells.” (07:03)

  • Muscles and liver store extra glucose as glycogen for later use, especially when fasting. (07:57)

• Insulin as the Key

  • Insulin is compared to a key allowing glucose into cells:

    “Imagine your cell is a house... to go into the house, it needs the key. The key is insulin.” (08:44)

  • Without insulin, glucose can’t get into cells, leading to elevated blood sugar levels.

Diabetes Explained: Types, Causes, and Complications

• Type 1 Diabetes – Body doesn’t produce insulin; patients take insulin.

• Type 2 Diabetes – Body becomes resistant to insulin, often requiring more “keys” (insulin) to open the “door” (cell):

  “It is a combination of insulin resistance and some insulin deficiency... you need, like, five keys to open the door instead of just one key.” (09:37)

• Risks of Unmanaged Blood Glucose

  • Chronically high blood sugar damages blood vessels, initially affecting eyes, kidneys, and nerves, and eventually larger vessels in the heart and brain. (11:35)

Dietary Decisions and Lifestyle Impacts

• Slower-Digesting Carbs & Balanced Meals

  • Dr. Kim:

    “We can choose carbohydrates that are slower digesting... If you have the whole fruit, it has fiber, it’s digesting more slowly, the glucose goes into the bloodstream more slowly.” (12:42)

  • Including protein and healthy fats helps balance blood sugar.

• The Power of Exercise

  “Exercise actually makes your body more sensitive... when you exercise, instead of five keys needed to open the door, you may only need three.” (13:41)

• Time of Day Matters

  • People are more insulin resistant in the morning due to hormone changes, so large breakfasts high in carbs may spike blood sugar more. (13:50)

Approaching the Holidays (and Life) with Balance

• Dr. Kim offers a reassuring perspective:

  “Don’t worry about the holidays. If you really wanted to focus on your health, I would say focus on the other 350 days of the year... don’t torture yourself during the holidays.” (14:35)

Notable Quotes & Memorable Moments

• Ping Huang (on CGM use):

  • “If I eat a sandwich for lunch, it’s going to really spike my blood sugar.” (04:22)
  • “I really just wasn’t exercising enough. And so it’s prompted me to exercise more.” (04:22)

• Sarah Kim (on insulin and resistance):

  • “The key is insulin. So if you don’t have insulin, that doesn’t happen and there’s a problem.” (08:44)
  • “[In type 2 diabetes] your body has to make extra insulin in order to do insulin’s job. And then over time, one can say that the cells that make insulin get exhausted...” (09:37)

• Sarah Kim (on holiday advice):

  • “Don’t worry about the holidays... indulge in the holidays, and maybe try not to indulge so much when it’s not the holidays.” (14:35, 14:54)

Timestamps of Important Segments

• Prediabetes prevalence and Ping’s CGM journey: 02:00–05:07
• How CGMs work and help with self-management: 03:13–05:03
• Glucose’s role in the body and insulin’s function: 07:01–09:14
• Types of diabetes explained: 09:14–10:24
• What happens when blood sugar is out of balance: 11:28–12:26
• Diet, exercise, and time-of-day effects: 12:42–14:06
• Holiday message from Dr. Kim: 14:25–14:54

Final Thoughts

This Short Wave episode offers a highly accessible, science-packed overview of blood sugar monitoring for both the curious and the concerned. Personal anecdote blends with medical expertise, demystifying CGM devices and making the case for thoughtful—but not obsessive—blood sugar management. Dr. Kim’s practical advice: focus on good habits across the year, and enjoy the holidays guilt-free.

Recommended for:
Anyone curious about CGMs, prediabetes, diabetes, or how daily choices impact blood sugar. Practical, balanced, and empathetic science journalism at its best.