Comparison between sprinting and sprint-jumping based on tests on a superflat world (Results will vary if you have to jump to cross terrain).
Sprinting: 100 blocks in 17.7 sec (~5.650 m/s), traveled 770 blocks till lost sprint from hunger (killed myself to reset hunger). 770 blocks at 5.650 m/s would take 2:16.
Sprint-jumping: 100 blocks in 14.3 sec (~6.993 m/s), traveled 400 blocks till lost sprint from hunger (killed myself to reset hunger). Traveling the same 770 blocks as above took 1:57, including stopping to eat once.
Thus it would appear that sprint jumping offers a large enough speed boost that it more than offsets the need to eat more often.