Can you concentrale while starving?

Yes it will affect your concentration and also your ability to retain information - you will also feel tired.

This is a terrible idea - you do know it won't work don't you?

If you starve yourself your brain will kick into action and after a while will switch into survival mode. Back when we were caveman (and women) food was scarce. What food there was had to be hunted or gathered and there were no guarantees. So when food was available early humans would eat as much as possible because the next meal could be a long way away. Famine was common so we evolved to cope with food shortages. When the body is starved of food the brain will assume that there is a famine. To ensure survival the brain will slow down the metabolism so fat stores are burnt slower and fewer calories are used. The body becomes super efficient at energy consumption using only what is absolutely necessary and storing any excess as fat for later. This was great thousands of years ago. This is not great any longer.

We have an abundance of food but if you starve yourself you will trick your brain into thinking there is a food shortage. Your metabolism will slow down, you will burn less calories and when you start eating again you will gain weight much faster as the body stores as much as it can in case no more food arrives.

If you wish to diet in this way consider the 5:2 diet. For 2 non-consecutive days per week you eat 500 calories (female) per day. The rest of the week you eat normally. 500 calories is about 6 eggs (roughly). Fast days must not be consecutive. Google it.