Unlike the first "Create Food" page (for food brand/name/quantity/serving info), the second "Create Food" page (for nutritional info) has Tab key support, but it's often broken. When tabbing, the page tries to autoscroll the newly focused field to the bottom of the window, so tabbing only works normally when the scroll…
For whatever reason, the first "Create Food" page lacks support for keyboard navigation; I can't use the Tab key to tab to the next field on the first "Create Food" page (for food brand/name/quantity/servings info), but I can on the second "Create Food" page (for nutritional info).