Healthy Food !!!
It is a big topic! just trying to diddle and fiddle around.Nutrition professionals usually do not use the term “healthy foods” because the fact that a food is healthy or not will very much depend on how much we eat of it how often, what our nutritional needs are, what else we eat in the diet, who is eating it, who it is for?  There is no single complete food that provides all the nutrients as we need. Also, every person in the family have different type & level of nutrient they need individually per day basis  so that’s one family meal  will not be suited each member of the family. Foods including a variety of different foods such as vegetables, whole grains, fruits, dairy products, legumes, lean meats, poultry and fish and enough fluids like water and watching portion sizes are key to a healthy diet.
Healthy eating and lifestyle are important to how we feel, look and how much we enjoy life. Eating a healthy diet will reduce the risk of diseases such as blood pressure, heart disease, stroke, obesity, diabetes, cancer. I would say everyone has to educate at least basic level about healthy food and its component. 
My experience  says most of the disease right start from the home kitchen.  It starts with what you feed to your kids and what we continue eating throughout the day to day life.
How can we make food healthy? the answer keeps simple, fresh and wholesome. I want to explain a bit more for the portion and serving size.
The portion is how much food you choose to eat at one time, whether in a restaurant or  from a package or in your own kitchen. A portion is 100 percent under our control what we decided to eat.
  • Serving Size is the amount of food listed on a product  so all of the nutritional values you see on the label are for the serving size the manufacturer suggests on the package.
    Once we understand the difference, it’s easier to determine how much to serve. When cooking at home: Offer the proper “serving” to each member of the family.
How do we control?
  1. When dining out: Skip the appetizers and split a large salad or main dish with a friend. 
  2. When ordering takes away  at home: Eat one slice of pizza instead of two, and order a small instead of a medium to split the family so the pieces are smaller. 
  3. Watching movies at home or at the theatre:  Don’t eat while watching TV or a movie or when you’re on the computer. It’s harder to control how much you’re eating if you don’t pay attention to what you’re putting in your mouth, and when. At the movies, share a box of popcorn, and avoid the free-refill tubs and skip the candy. 
  4. Avoid Chinese and  Eat much as you like a buffet.  End of the day your stomach is fix and whatever variety or food you can eat full not more than this so why we go these place better we should go decent place and get what you like. 
  5. At snack time: Never eat straight from the bag or box. Measure out snacks, including fruits and veggies, into an appropriate portion, sizes before giving them to your kids.
These are general serving sizes 
  • 1 slice of bread
  • about 200 gm  rice or pasta (cooked)
  • 1 small piece of fruit (super-large apples are 2+ servings)
  • 1 wedge of melon
  • 80 ml fruit juice
  • 200 milk or yogurt
  • 50 gm of cheese
  • 80 gm  meat, poultry or fish 
 Healthy Cooking Idea 
Cook and use fresh produce as much as possible.Fresh, so there not going to be added addictive to preserved food such as sugar, salt, sulfur, benzoate, brine  and so on.
Sourcing healthy produces and using an unhealthy cooking technique doesn't make sense for example if we buy fresh from the fish market to battered deep fried where  we could be baked / grilled that fish with same spice or more ever poached adventurously with your favourite herb and spices. 
Count Total Calories What You Need and Stick within line Splitting at least 5 Meal a day. As average calories, we need for the day is about 2200 to 27000.
I use the website below to count calories, in general, & it's very easy and cover all most of all ingredients in the different form and it's  free.
http://www.nutracheck.co.uk/CaloriesIn/
Customize your food, even though burger goes with a slice of cheese,  you can avoid easily replacing with an extra slice of cucumber or slice of meat with fatty patties. 
Go for vegetarian or wholesome produces rather than processes like a slice of salami/ ham  rather than with a slice of chicken or vegetable. 
Greek yoghurt to light and low-fat yoghurt, ghee to olive oil, refine flour to wholemeal flour, white bread  with wholemeal brown bread, frozen / can / preserved food to fresh food, cream to low-fat milk. 
  • Stock up on heart-healthy cookbooks and recipes for cooking ideas. keep it simple 
  • Cook the wholesome simple dish with least ingredient balance of  carbohydrate, protein, green.
  • Use grades of meat rather than prime  and be sure to trim the fat off the edges before cooking.
  • Use cuts of red meat and pork labeled loin and round as they usually have the least fat. With poultry, use the leaner light meat (breasts) instead of the fattier dark meat (legs and thighs) and be sure to remove the skin and trim the fat.
  • Make recipes or egg dishes with egg whites, instead of egg yolks.  Substitute two egg whites for each egg yolk.
  • For recipes that require dairy products, try low-fat or fat-free versions of milk, yogurt and cheese.
  • Use reduced-fat, low-fat, light or no-fat salad dressings (if you need to limit your calories) on salads, for dips or as marinades.
  • Use and prepare foods that contain little or no salt.
Basic Snack and Natural Food Idea
Try healthy way of the cooking idea such as instead of frying, shallow frying grilling do with steaming, baking, poaching.
Instead of stir-fried we can do blanch.
Instead of pouring oil we can spray every little help make a difference to live.
Try at least once a week raw food  for day and another day the vegetarian same way we can try vegan, gluten free. It depends on how deep we want to go. I would suggest going with slow and steady.
Try light meal such as steamed edamame bean instead deep fried peanuts, deep fried chips.
Replace refine sugar with honey, salty potato crisps to raw nuts, or roasted no salt nuts. animal fat, lard  with cold press olive oil, cook with less salt,
fizzy drink to simply still water or fresh cold press juice or smoothie.
Always make meal balance of carbohydrate, protein, green vegetable.Eat same in total for the day but small portion short time interval and many meals.
I always try to make one meal under 500 calories with about 120  gm of protein can be meat chicken, fish, lentil, tofu balancing carbohydrate / Starch of  about 100gm, and about 80gm of green vegetable. That mines from 500 calories from each meal will give us more snacking or light dessert opportunities.
All above figure are from my head there is no data, factor or based formula to prove, it all it based on my 18 years of cooking experience and also used to be developed  special meal for 68 global major airlines in worldwide and recently I attended Nutrition classed and I’m qualified Nutritionist and again I’m doing and writing it  for my interest.