I already like you girl! There are a lot of issues at play here. What you eat definitely does have an effect on how you smell and taste. Pay attention to what you eat prior to sex although your overall diet plays a big part not just your recent meals. Try, like you were saying, to eat some sweet fruit as your meal before you have sex. Eating meats especially red meat does make it more salty and acidic. My guess is that with your new focus on protein your meat intake has increased.
The pH level of your vagina is very important. You may be more acidic than you should be right now. Try using an organic apple cider vinegar and water douche the perfect pH level and then start taking some really good, active probiotics to get your pH level in check.
Watch out for frequent douching or using over the counter douches because they can kill the good bacteria and allow for an overgrowth of bad bacteria like yeast and that defeats the purpose and makes things much worse. A couple hours after your apple cider vinegar douche you can also douche with a probiotic douche or douche with actual yogurt to introduce the good bacteria directly just be sure to use plain yogurt since you do not want to get sugar in there since yeast feeds on sugar.
Since you are losing weight your body is detoxing and ridding itself of unwanted stuff so for a while this element will be unavoidable. So, take a shower prior to sex and use a flavored lube like Patricia recommended or honey dust flavored powders you brush on lightly to counteract any unavoidable smells and tastes. As you try new things check in with your partner to see what is working.
By the way, this is a two way street. There are many things, like diet, that effect the taste of semen as well. Maybe you could both set out to have the best tasting oral sex ever. That way the focus isn't all on you. Good luck and happy sexing!