WL4I has no calorie counting or portion restriction. The advice is to eat until satiation - but not until feeling stuffed. This makes the calorie breakdown difficult. The diet generator will create 11 days of basic meal plans based on your food preferences. The 4th day is typically a fruit and veggie day. After the 11 days of meal plans there are 3 days of "cheat" meals. Here is an assessment of my calorie breakdown:

MEAL PLAN 1
Meal #1: Chicken
Meal #2: Fruit Salad
Meal #3: Fish Filet
Meal #4: Cottage Cheese

At a guess I would eat 2 chicken breasts, 4 cups fruit salad, 2 cups cooked fish, 2 cups of cottage cheese.
Calorie breakdown: 1,876 total, 33g fat (16%), 159g carbs (32%), 234g protein (52%).

This day very much resembles that of a bodybuilder's "cutting" phase (i.e. reducing fat whilst maintaining muscle). Reduced carb and high protein. But how does this affect the person who is not engaging in weight training? The calorie level is low - but at a good level for fat loss. For me - below 1600 or so cals results in muscle loss. The protein level here is quite high (especially for a sedentary person).

It seems unlikely that a person (who is not actively pursuing muscle growth) could sustain this kind of protein intake.

MEAL PLAN 2
Meal #1: Scrambled Eggs
Meal #2: Chicken
Meal #3: Mixed Nuts
Meal #4: Sandwich (any type)

My calculations this were: 1,768 calories, incl 97g fat, 93g carbs, and 132g protein.

What Is The Outcome?

I think we're getting the picture. This is a lower carb diet - and yes it can work for some people. The combination of caloric reduction, the thermic affect of feeding (i.e. from consuming the protein), will aid in fat reduction.

However - what concerns me is the same thing that concerns me about many diets. This eating is probably not sustainable for most people. This means that at some stage you will return to eating a lot more carbs (and/or a lot more food!) - and on comes a lot more fat. How do you choose to eat for the rest of your life?
The second thing is the higher amount of protein - this is unnecessary except for those engaged in heavy weight training.

Low carbohydrate levels - Now this can be contentious and I'm not going to argue about low-carb vs low-fat. Some people simply eat too much carbohydrate for their activity level. This is not necessarily advocating very-low-carb diets, however some people can benefit from sourcing their carbs from more wholesome sources (such as oatmeal), and not feel the need to eat starchy carbs at every meal.
However not everyone is that sensitive to carbs, and do not necessarily benefit from reducing carbs.

What Can Be Improved On?
Eat some more whole carbs, and reduce the protein. Then you would have a diet that looks quite similar to what I'm eating now! (except I eat about 5 times a day).
Introduce some solid weight training into the mix. Make use of that protein. Increasing your muscle will boost your metabolism further, and help you to prevent relapses.

What About The Rapid Weight Loss?

Weight loss comes from 3 areas - muscle, water, and fat. As many know rapid weight loss (> 2-3 pounds per week) is often due to significant water loss and is also typically a short term thing. This is not to say that some people (often those who are very overweight) can experience continual sustained weight loss for months.

What is Water Loss?
Carbohydrates are our fuel source. When we eat them they provide us with the energy for everything from metabolic function to fueling physical exercise. Energy from carbohydrate is stored as glycogen - typically in the muscles and liver. When we reduce our carbohydrate intake (either by deliberately lowering carbs, or an overall calorie reduction) then our body will begin to make use of the glycogen. Glycogen is typically stored with a lot of water - and water weighs quite a lot - as the glycogen is used up - the water is flushed away.

What Good Things Can Be Learnt From WL4I?

Eating 4 times a day - Eating more often keeps energy levels consistent and assists in keeping metabolism high. Good protein sources - Protein is an essential nutrient, however some protein sources can be laden with saturated fats. Skinless poultry, fish and seafood, nuts, cottage cheese etc, are all good choices. Learning to eat short of satiation - There are some people that love logging every food item everyday - but I am not one of them. Understanding when our body has had enough is a useful skill.

Coming Off The Diet

As many know, I am not a fan of the "dieting" mentality - the roller coaster of going on and off diets. This is no way to permanently manage your weight and can take a real toll on your thinking and motivation. However there are many situations where a structured eating plan is warranted.

In all honesty, if you aren't planning on changing your eating habits for good, then the chances are, you will only gain back the same fat you lost before. So what can you take out of WL4I and use?

I believe the biggest risk of subsequent weight gain will occur if you rapidly increase carbohydrates. Refined carbohydrates are (unfortunately) a staple of the western diet, and quite frankly should be minimized as much as possible (foods like pastries, cakes, doughnuts, white breads and pastas etc.) If you are a person that enjoys lots of carbs then you must be very careful to gradually introduce more carb into your diet - and to watch the results closely.

Learning to make good choices
It is up to us to make good food choices for the rest of our lives - or else this is all for nothing. This doesn't mean you can't enjoy a piece of cake at your kids birthday - or that you can't go out for dinner with friends. It just means that for most of your meals you learn to choose lean proteins, vegetables, whole carbs, and healthy fats. Believe it or not, there might come a time when you actually (gasp!) enjoy it. I look forward to my oats every morning - I can't even remember the last time I ate some sugary cereal.

Be committed to learning and understanding some basics of nutrition. It's a minefield out there. You don't want to be scrutinizing every food label as you walk down the aisle (try doing that with a couple of grumpy kids on hand). It's helpful to be familiar with a whole bunch of foods that are good for you.