甘露庚酮糖（英语：Mannoheptulose）是一种庚糖，即有七个碳原子的单糖。它是己糖激酶的抑制剂，通过竞争性地与己糖激酶结合来阻断葡萄糖的磷酸化。结果是葡萄糖的降解被抑制。D-甘露庚酮糖最早在鳄梨中发现。

有研究指出，甘露庚酮糖会抑制胰岛素分泌。 This inhibition occurs because when mannoheptulose is present the glycolysis is inhibited (because there is no production of glucose-6-P) therefore no increase in ATP concentration which is required to close the KATP channel in the beta cells of the pancreas causing a diminution of calcium entry and insulin secretion.

Mannoheptulose is a hexokinase inhibitor. It is a heptose, a monosaccharide with seven carbon atoms. By blocking the enzyme hexokinase, it prevents glucose phosphorylation. As a result, the breakdown of glucose is inhibited. It is found as D-mannoheptulose in avocados.