Food and other cravings, and guarding the senses How do I deal with food cravings or craving in general? According to the four efforts I should replace craving with the disadvantages. Can loving-kindness also work? I feel like concentrating on impermanence and on the disadvantages, in the midst of an emotion, works not as effective. I guess one needs to strengthen one's conviction in both?
I read the Buddha saying about guarding the senses -- but I doubt that the Buddha meant not looking, not hearing (etc) at things. While it can be advantageous, I think perceiving them differently is much more important. Can someone answer what "sense-guarding" means, or "not grasping at the beautiful", and how do I do it?
I feel like concentrating on impermanence and on the disadvantages, in
  the midst of an emotion, works not as effective.


Yes, that's because what impermanence is not the one and only thing which need to be considered to uproot the cravings. No matter how hard you try can you get satisfied with any kind of cravings? It can be food. If you are fully satisfied or 
if you've reached ultimate satisfaction would you need to eat food again? No right. Our mind always looking for this satisfaction and it always get cheated by things like nice / delicious food etc. And then we keep running after that. It's true we feel happy when we eating that, but those doesn't full fill our mind's expectation of ultimate satisfaction. Why is that? That's because everything in this world is insatiable. That's the reality | truth of this world. Impermanence is just a one quality / attribute of that nature. Once you realise this, you should think twice before running after mirages. Because no matter how hard you run you won't be satisfied only thing you get is the tiredness and other occurrences while running. And then you should see danger of those kind of actions. Not knowing the gratification (assada), the danger (adinava) and how to escape from (nissarana) are the root causes for cravings. When you think about this and when you realise the uselessness of cravings it will start to get reduced.


  I read the Buddha saying about guarding the senses -- but I doubt that
  the Buddha meant not looking, not hearing (etc) at things.


Again this links to the above. How you guard your senses is thinking about the uselessness of those by knowing the gratification (assada), the danger (adinava) and how to escape from (nissarana). This doesn't mean that not looking at things but controlling the attachment / craving / gratification (assada) towards the thing you look at and the action of looking by thinking of danger. Which will realise you the gratification (assada), the danger (adinava) and how to escape from (nissarana) the thing you looked at and the action of looking. And finally you start to escape from the part of attachment or the gratification of that. Because that's what drives you towards the danger.

If you think about the bait given to a fish. Is the food in the bait given pain to the fish? or the hook (used to catch the fish with the fishing rod) given the pain? 

If you the answer is hook, then if you just place the hook without the food (bait) does the fish get caught or the fish get pain? 

No right. Then if you think deeply you will understand that the food (bait) is given pain to the fish. Like wise gratification (assada) gives the danger (adinava) to us. We can't blame fish because it doesn't know that it's a trap. It's called Avidya (ignorance). For us it's the same. Poor us! we are covered with Avidya (ignorance) so we don't realise the truth, we don't realise it's a trap, and we get attached to things and keep running after gratification (assada) of those, thinking those will give us ultimate satisfaction. But it will never happen. Because the world is insatiable. Once you see this you will find a 
to escap (nissarana) from gratification (assada). Don't misunderstand this escape is not from the outer world things, but from the attachment / cravings.

Where does the ultimate happiness and satisfaction actually do exist, which is looking for by our minds? -> It's called Nivana, Nirvana or Enlightenment

With Metta..!