Part 2:
How Insulin and Glucagon Impact Blood Sugar, Brain Function, and Flares in Chronic Illness + ED Recovery
From a Registered Dietitian Specializing in Eating Disorders and Cooccuring Chronic Illness and Chronic Conditions
From a Registered Dietitian Specializing in Eating Disorders and Cooccuring Chronic Illness and Chronic Conditions
Fasting and carb restriction are often marketed as tools to reduce blood sugar and inflammation. But in my work with clients who live with POTS, MCAS, EDS, autoimmune conditions, or disordered eating, these strategies often make things worse and not better. Each of these posts is intentionally brief and bite sized. Stay tunes for a part 3 coming soon. But for now, here’s what’s really happening behind the scenes in the triad between glucose, insulin, and glucagon and how this relates to symptoms:
Glucagon increases, which tells the liver to release stored glucose
Cortisol rises, acting as a backup to keep blood sugar stable
Gluconeogenesis kicks in and your body starts breaking down muscle to make glucose
While this works short-term, over time it creates stress on the system and leads to:
Sleep disturbances
Fatigue or crashes
Blood sugar spikes in the morning (dawn phenomenon)
Hormonal dysregulation
People with complex conditions often have:
Autonomic nervous system dysregulation
Unstable blood pressure and heart rate
Histamine sensitivity
Altered cortisol rhythms
In these bodies, fasting or skipping meals can lead to:
Worsening dizziness, fatigue, and GI symptoms
Increased inflammation or MCAS flares
Higher anxiety or panic due to blood sugar crashes
Poor recovery and sleep
The brain is very sensitive to energy fluctuations. Blood sugar crashes can trigger:
Anxiety or panic
Poor cognition
Less cognitive flexibility in thought processes
Mood swings
This is especially true for individuals with a history of anorexia nervosa, ARFID, or hypoglycemia.
If you’re navigating life with a complex chronic illness or working toward eating disorder recovery, your body needs more and not less—support which often requires including some carbs at every meal and snack. This can help to:
Regulate blood sugar and brain chemistry
Lowers stress hormone output
Enhances clarity, mood, and resilience
Reduces flares, crashes, and symptom spirals
*Note: This post and all contents of this website are provided for informational purposes only and are not medical advice or intended to be used as such. The explanations provided above describe the typical biochemical programming of insulin and glucagon in individuals without insulin-dependent diabetes. In people with Type 1 diabetes or advanced insulin-dependent Type 2 diabetes, the body either does not produce insulin or does not respond to it effectively. This alters the hormonal balance and glucose regulation described here. In these cases, external insulin is necessary to support blood sugar control, and glucagon responses may also be impaired due to pancreatic dysfunction.