4 kilos is abut 9 pounds. I'm assuming you want to get down to 185 pounds? 9 pounds in a month is do-able, but is certainly on the high side. Start by drinking a lot of water (about 2 liters a day) and try to get some aerobic exercise 6 out of 7 days (start slow if you are not currently exercising). Eat lots of veggies, whole grains and lean protein. Include a small amount of healthy fat. Pick a calorie count that is healthy for your goal weight and stick to it. Do not go under 1200 calories a day. This MAY be the ticket to losing the weight, but you need to keep going at the end of the month, or the weight will come right back. Good luck!