Obligatory math because nerd:

Assuming each ration contains roughly [hider=4* oz]
*4 oz. of jerky translates to roughly 113 grams. At roughly 40% protein by volume, that would be 45 grams of protein. The average adult male human needs 56 grams of protein per day, while the average adult woman needs 46 grams. The dried fruit and hard tack would all have small amounts of protein, while the nuts would have a considerable amount of protein. Likely more than enough to account for the daily needs of an adult human. Assuming bug bears would favor rations that lean more heavily on the meat, 4 oz. of jerky (which would be 1/8th the total weight of the 2 lb. ration) seems appropriate.
[/hider] of jerky, all 8 rations would collective contain 2 lbs. of jerky.

Owl bears weigh between 1300 to 1500 lbs, canonically, putting them on par with polar bears in terms of weight. On average, polar bears need to consume more than 4 lbs of fat to meet their 12,000 calorie daily intake requirements. However, being large carnivores, they're capable of eating well over 20,000 calories in a day when food is abundant which would be closer to 7 lbs.

Jerky has roughly 80 calories per ounce, so 4 oz from one ration would be 320 calories and all 8 rations would put it at 2,560. A bit more than 1/10th the daily caloric intake of a predator the size of an owl bear, and dramatically less calories than would be available in an equal serving of fat (which has well over double the calories per ounce as jerky.)
All of which is assuming Brutrumukk's rations are what's leftover from his time as a bug bear.

The metaphor here would be something like offering a hungry, adult man a child's portion of Chinese food and asking if he's still hungry.