V teoriji je ravno nasprotno.

No, tudi v praksi, a vprašanje, koliko je prenosljivo na vsakdanje situacije:
The increase in muscle glycogen concentration from the end of exercise to the end of the 24 hour recovery, as assessed by muscle biopsy, was greater by approximately 50% (106.1 ± 11.7 mmol/kg wet weight vs. 71.5 ± 6.5 mmol/kg wet weight; p = 0.02) when foods with a high GI were consumed.
Hitrost sinteze glikogena je povezana s količino inzulina v krvi. Po tej logiki, bi morali visoko-GI obroki biti boljši, sploh ko gre za kratka obdobja regeneracije (daljše vzdržljivostne tekme, etapne dirke, veliko treningov ... ). V dejanskih situacijah je vse zelo odvisno.
when the time between 2 bouts of demanding exercise is measured by days, compared with hours, no evidence suggests that high GI meals replenish glycogen stores any better than low GI meals, providing that an adequate amount of CHO is ingested.
V nobenem primeru torej nizko-GI obroki niso boljši, kvečjemu enako ok in enako nevredni obremenjevanja. Edina možna povezava, na katero lahko pomislim ob predlaganju nizko GI hrane športnikom je v zadnjem obroku pred tekmo, ko obstaja nekaj namigovanj, da bi tak obrok na račun boljše izrabe telesnih maščob, lahko prihranil več glikogena za poznejše obdobje tekme (jasno, nanaša se na vzdržljivce):
In conclusion, there is good agreement that rebound hypoglycemia can be prevented by the use of low GI preexercise CHO meals, although this has not resulted in improved athletic performance in most cases.
Vprašanje, na račun koliko performanca in kako je s tem v praksi. Jasno, niti približno tudi ni aplikabilno za koga drugega kot ultramaratonce.

Za boljši pogled v to področje predlagam tole meta študijo, ki ima čudovit abstract in iz katere so zgornji citati:
Although attractive, the use of GI in sport nutrition has received only partial support from available experimental evidence. At the biochemical level, consistent evidence has been attained to suggest that GI manipulation can determine variations in adipocyte lipolysis, plasma free fatty acids levels, and lipid and CHO oxidation rates during exercise. However, when the effects of GI manipulation have been assessed at the functional level, the results have been inconsistent, with evidence of improved exercise performance in some studies, but not in many others.
http://www.jacn.org/content/28/4_Supplement_1/455S.full