Nick NorwitzMD PhD, Oxford-Harvard | Metabolic Health Educator | “Stay Curious”

Can Kale Really Spike Your Blood Sugar More Than Chocolate?

18 May 2025 · 1 min

Watch on YouTube

1:19

In this video, the creator conducts a personal, repeated experiment to compare the blood‑glucose response to cooked kale versus two dark chocolate bars. Over six separate days, he tests each food three times, consuming realistic portion sizes: about four cups of raw kale (cooked down, ~8 g net carbs) and two chocolate bars—a 95 % dark, stone‑ground Tezo bar (2.5 oz, 12 g net carbs) and a 73 % dark bar (2.1 oz, 27 g net carbs). He does not attempt to carb‑match the foods, intentionally biasing the design toward chocolate causing a larger spike due to higher carbs and glycemic index. Glucose readings show that kale consistently produces a higher blood‑sugar spike, while chocolate never exceeds a 21‑mg/dL rise. The surprising outcome challenges assumptions about the glycemic impact of leafy greens versus chocolate.

Chapters

I tested kale and chocolate 3 times each on 6 different days. I used 2 different chocolates: a 95% dark chocolate, a stone-ground chocolate from the brand Tezo, which is my go-to, no affiliation, and a 73% dark chocolate. I did not try to carb match them. I actually ate the amounts a normal person might. So for kale, I cooked down about 4 cups of of raw leaves, which amounts to about 8 grams of net carbs. Not much at all in terms of net carbs. And for the chocolate, I ate the bars because real people don't eat just one square. And if you do eat just one square, please feel your forehead for me. You might find there's a unicorn horn there. Anyway, the 95% bar was 2.5 ounces and the 73% bar was 2.1 ounces with net carbs of 12 and 27 grams respectively. So if there was bias, and there was by design, it was in favor of chocolate spiking my blood sugar more, not kale, due to the higher carbs and the higher glycemic index of the chocolate. But that is not what happened. To the contrary, the kale reliably spiked my blood sugar, and the chocolate never spiked it more than 21. Isn't that interesting?