The present invention relates to slowly digestible storage carbohydrates (starch, glycogen) having a branching degree of at least 8.5% and a side chain composition comprising at least 10% of DP 5-7. Said slowly digestible carbohydrates can be produced by treating the substrate (glycogen, starch) from a native source with a glycogen branching enzyme derived from Rhodothermus obamensis, Rhodothermus marinus, Deinococcus radiodurans or Deinococcus geothermalis.