Why Losing Muscle May Be Making Your Blood Sugar Worse
- t2diabetesnetwork
- 3 days ago
- 4 min read
Written by Clare Koning, RN, PhD June 2026 5 min read
Key Highlights
✅ People with T2D have a 3-fold higher risk of muscle loss compared to those without diabetes
✅ Muscle is the body's primary glucose disposal organ, so losing it directly worsens insulin resistance
✅ T2D causes a distinct type of muscle loss that differs from normal aging
✅ Resistance training slows muscle loss, and may be more important than cardio for people with T2D
✅ GLP-1 medications, while effective for weight loss, may accelerate muscle loss without adequate protein and resistance training
When people think about the complications of type 2 diabetes (T2D), they typically think about the eyes, the kidneys, the heart, and the feet. Muscle rarely makes the list. But skeletal muscle is the largest glucose disposal organ in the human body, responsible for absorbing up to 70-80% of insulin-stimulated glucose uptake during a meal. When you lose muscle, that capacity shrinks, and blood sugar control gets harder.
This relationship between T2D and muscle loss, increasingly referred to as diabetic sarcopenia, is one of the most underrecognized and clinically important aspects of living with the condition.
What Diabetic Muscle Loss (Sarcopenia) Actually Is
Sarcopenia is defined as the progressive loss of skeletal muscle mass, strength, and function. It is classically associated with aging. But research published in Frontiers in Endocrinology has demonstrated that T2D-related muscle loss is a distinct entity, with a different pathological pattern than age-related sarcopenia. Where normal sarcopenia primarily affects fast-twitch Type II muscle fibres, T2D targets the slow-twitch, oxidative Type I fibres that are most important for sustained, endurance-type activity and metabolic regulation.
A 2025 review published in Diseases identified key risk factors for diabetic sarcopenia: poor glycemic control (HbA1c above 8%), longer diabetes duration over five years, low BMI, and reduced levels of vitamin D and insulin-like growth factor-1 (IGF-1). Importantly, the review found that people with T2D have a 3-fold higher risk of sarcopenia compared to those without, and that 8.2% of people with newly diagnosed T2D already have sarcopenia at the time of diagnosis.
The mechanisms are multiple and reinforcing. Chronic elevated blood sugar promotes the accumulation of advanced glycation end-products (AGEs) in muscle tissue, impairing contractile function. Insulin resistance itself impairs the anabolic signalling pathways, particularly the mTOR pathway, that drive muscle protein synthesis. And elevated cortisol, common in people with poorly managed T2D, directly accelerates muscle protein breakdown.
More muscle mass, and not just less body fat, is critical to lowering your risk for type 2 diabetes, a study by UCLA's Dr Preethi Srikanthan and colleagues suggests.
T2D causes muscle loss through at least four distinct biological mechanisms: glycation of muscle proteins, impaired anabolic signalling, inflammation, and elevated cortisol. This is not just aging. It is disease-driven.
The GLP-1 Weight Loss Warning
One timely dimension of this issue relates to the extraordinary popularity of GLP-1 receptor agonists for weight loss. These medications are effective, and their benefits for glycemic control, cardiovascular health, and kidney protection are well-documented. But rapid weight loss from any cause, including GLP-1 therapy, carries a risk of significant muscle loss alongside fat loss.
A 2025 review in Nutrients specifically examining creatine supplementation, exercise, and T2D noted that for people with pre-existing insulin resistance and sarcopenic risk, losing weight rapidly without concurrent resistance training and adequate protein intake may worsen the muscle-mass deficit even as metabolic markers improve.
This is not an argument against GLP-1 therapy. It is an argument for pairing it with structured resistance exercise and protein-focused nutrition, a combination that evidence strongly supports for preserving muscle during weight loss.
What the Exercise Evidence Shows
A 2025 systematic review and meta-analysis published in Diabetes Research and Clinical Practice, examining 19 randomized controlled trials in older adults with T2D, found that resistance exercise training significantly improved HbA1c (mean difference: -0.51%, p < 0.0001) and fasting blood glucose, alongside meaningful improvements in muscle mass, strength, and body composition.
A 2025 review in Metabolites comparing aerobic, resistance, HIIT, and combined training protocols concluded that combined aerobic and resistance training produced the best overall metabolic outcomes, with resistance training showing particular advantages for muscle preservation and insulin sensitivity in people with T2D.
The key finding from the meta-regression work is that training effect matters: the greater the strength gain, the greater the HbA1c reduction. This points toward progressive overload, gradually increasing weight or resistance, as the mechanism behind blood sugar benefits, not simply moving the body.
Practical Targets
For people with T2D, the current evidence supports at least two resistance training sessions per week targeting major muscle groups, combined with adequate dietary protein (generally 1.2 to 1.6g per kg body weight daily, adjusted for kidney function). Both are underutilized in standard T2D care.
Talk to your diabetes education team about incorporating resistance training, even if it is bodyweight exercise at home, into your management plan. This is not supplementary to your diabetes care. For many people, it may be one of the most impactful interventions available.
For more on exercise and T2D, visit the T2D Network's Healthy Lifestyle page or join our network for weekly insights.
