As you have only been diagnosed for a few days your doses of insulin will be very much determined by your doctor/nurse and they may need to change them quite a bit at first. The rapid insulin doses than they have prescribed you will be prescribed under the assumption that you are eating a normal healthy diet including some starchy carbohydrates.
It is a very good idea to learn to count the carbohydrates in your meals and to keep a diary of your meals, carb counts, blood glucose levels before and 2 hours after meals. Armed with this information you will begin to realise the effect of your rapid insulin, eventually learn how to adjust your insulin to the meals you eat. ( there are courses both online and in person)
The tools you need for that are a little book with a list of foods and the carbohydrate they contain (the best ones in my opinion list the carbohydrate per 100g rather than odd portion sizes) and some scales. An alternative which could be helpful at first is a little book called carbs and cals which had photos of a wide variety of foods/ meals of differing portion sizes along with their carb counts.
http://www.carbsandcals.com/ Remember that there are carbohydrates in veggies/fruits /dairy as well as starches.
I try to eat a lot of vegetables, some fruit, protein from meat and fish; I eat a lot of chicken and try to eat fish at least twice a week. I don't often eat dessert (fruit is better) and when I took sugar used sweetener in drinks rather than sugar. When I first developed T1, my dietitian told me to divide the plate into quarters ,a quarter protein, quarter starchy carbs and half the plate veggies. With a piece of fruit or some stawberries/blueberries plus if you don't drink milk some yoghurt or a small piece of cheese you have a balanced meal (bit more difficult with things like stir fries but it suggests the relative proportions.
I personally tend to choose starchy carbs that have a lower glycemic index ie brown basmati rice/ boiled new potatoes, al dente brown pasta; I would avoid most breakfast cereals as they I often very high in sugar (I eat porridge with a few berries most mornings) . It is difficult to find lower GI breads in the UK. A lot of people eat Burgen but also find some of the very grainy breads taste good and are lower GI. Pulses are a good low GI starch.
http://www.glycemicindex.com/
(basic info in the FAQs, the newsletter has a lot of interesting info each month and some recipes.
This basic pattern is what I still do seven years later. I've learned to adapt it and to adjust my dose age so that I can eat a dessert when I go out to dinner or adjust my insulin if I go to a friends house and am presented with a big bowl of pasta. I just don't do it every day. Take aways can be difficult to give the appropriate insulin for(carbs and cals book can help here). The big problem is that the sauces offered by Indian and Chinese restaurants are very varied and some are very high in sugar. It probably gets easier; I live in France so don't get much practice.
I also find exercise is an important part of my diabetes 'tool box' (I know you asked about food but I think it's equally important)
This sort of approach to diabetes control has worked for me and I 've managed to keep very good blood glucose control .
Yes I put on some weight when I first went onto insulin because I had lost so much before diagnosis. I now just keep an eye on things, if I have been eating a bit too much or exercising a bit too little and put on weight, I cut back a bit. I
