Insulin: Friend, Foe, or just Misunderstood?
Insulin 101
Insulin is made in your pancreas (specifically, the beta cells of the islets of Langerhans). I’ve always pictured this like Vikings on an island—jumping into their longboats and heading off to a glucose war. When you eat, your blood sugar rises, and insulin is released into your bloodstream to “unlock” your cells so they can pull in that sugar. Think of it as your body’s delivery driver—dropping glucose off at muscle, liver, and fat cells. Without it, glucose just floats around in your blood, where it’s toxic to your vessels and nerves if it hangs around too long. With too much of it, too often? The system gets jammed—and when that happens, sugar and fat don’t get stored or used properly, leading to higher blood sugar, easier fat gain, and eventually long-term damage (Petersen & Shulman, 2018; Merz, 2020).
Why it spikes
Big servings of fast carbs—like your grandma’s delicious apple pie topped with vanilla bean ice cream—shoot blood sugar up quickly. Your pancreas responds with a flood of insulin to bring levels back down. Protein can also bump insulin (especially whey), but it usually doesn’t skyrocket glucose the same way carbs do (Holt et al., 1997; Pal & Ellis, 2010).
When does it count as a spike?
There isn’t one perfect definition, but here’s a practical guide (American Diabetes Association, 2025):
Fasting glucose (no food for 8 hours): Normal is <100 mg/dL, prediabetes is 100–125, diabetes is 126+.
Post-meal glucose (1–2 hours after eating): The ADA recommends keeping it under ~140 mg/dL in healthy individuals. Above that repeatedly? That’s when trouble starts.
A1C (Hemoglobin A1C): This measures your 3-month average blood sugar by tracking how much sugar sticks to your red blood cells. Normal is below 5.7%, prediabetes is 5.7–6.4%, diabetes is 6.5%+.
Why do spikes matter?
One spike won’t wreck you. But constant spikes? That’s when artery walls can start thickening, inflammation cranks up, and your body starts the dangerous road of becoming insulin resistant. Glucose hanging around in your blood damages vessels and nerves over time, and your pancreas constantly “shouting” to pump out more insulin just burns the system out faster (Monnier et al., 2006; Ceriello, 2008).
Insulin resistance—the canary in the coal mine
When you flood your system with insulin day after day, your cells stop responding to the signal. It’s like texting your buddy 100 times a day—eventually he ignores you. Your pancreas responds by shouting louder (pumping out even more insulin), which only makes things worse.
This is what you need to know: your muscle cells normally act as the main warehouse for glucose, storing it as glycogen. But once those glycogen stores are full—or when your muscles stop “listening” because they’ve grown resistant—glucose has to go somewhere. The body doesn’t waste energy, so insulin directs that overflow into fat cells, where it’s converted and stored as body fat. That’s why insulin resistance often shows up first as both rising blood sugar and easier fat gain, especially around the belly. Over time, this sets the stage for type 2 diabetes, cardiovascular problems, and metabolic decline.
How to Keep Spikes in Check
Lead with protein and veggies. Eating them before carbs lowers the spike (Shukla et al., 2015).
Fiber is your ally. Beans, oats, and veggies slow absorption and flatten glucose curves.
Walk it off. A 10–15 min stroll after meals helps muscles soak up sugar (Reynolds et al., 2016).
Lift heavy. Muscle is a glucose sponge. The more you’ve got, the better your body handles carbs (Merz, 2020).
Glycemic Index (GI) Isn’t Perfect
GI looks at how single foods affect blood sugar in a lab, but life isn’t a lab. Milk has a low GI but spikes insulin, while two guys can eat the same bagel and have completely different responses. Continuous glucose monitor studies show that personal biology, sleep, and stress can change your response to the same food (Zeevi et al., 2015). Use GI as a loose guide, not gospel.
Bottom Line for Men
Insulin is essential—you just don’t want it in overdrive all day.
Keep fasting glucose <100, post-meal under ~140, and A1C under 5.7%.
Too many spikes → insulin resistance → easier fat gain + health decline.
Eat like a man with a plan: protein + veggies first, carbs second.
Move after meals and keep building muscle.
Infrequent spikes aren’t the enemy—that pie isn’t going to eat itself. However, Constant spikes are going to be a major problem.
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References
Petersen MC, Shulman GI. Mechanisms of insulin action and insulin resistance. Endocr Rev. 2018;39(5):830–850.
Merz KE, Thurmond DC. Role of skeletal muscle in insulin resistance and glucose uptake. Compr Physiol. 2020;10(3):785–809.
Holt SH, Miller JC, Petocz P. An insulin index of foods: the insulin demand generated by 1000-kJ portions of common foods. Am J Clin Nutr. 1997;66(5):1264–1276.
Pal S, Ellis V. The acute effects of whey protein on postprandial lipemia and insulin responses in overweight/obese individuals. Am J Clin Nutr. 2010;91(4):966–971.
American Diabetes Association. Standards of Medical Care in Diabetes—2025. Diabetes Care. 2025;48(Suppl 1):S1–S194.
Monnier L, et al. Activation of oxidative stress by acute glucose fluctuations compared with sustained chronic hyperglycemia. JAMA. 2006;295(14):1681–1687.
Ceriello A. Postprandial hyperglycemia and cardiovascular complications of diabetes. Diabetes. 2008;57(6):1349–1355.
Shukla AP, Iliescu RG, Thomas CE, Aronne LJ. Food order has a significant impact on postprandial glucose and insulin levels. Diabetes Care. 2015;38(7):e98–e99.
Reynolds AN, Mann J, Cummings J, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Diabetologia. 2016;59(7):1479–1491.
Zeevi D, et al. Personalized nutrition by prediction of glycemic responses. Cell. 2015;163(5):1079–1094.
