DISCUSS WITH YOUR PHYSICIAN FIRST, NOT SUITABLE FOR EVERYONE
Low carb diet works very well. What I hate about low carb diet is that you can not have any fruits and you have to avoid many healthy vegetables as well. It just sounds so unnatural and contra-intuitive to avoid fruits and veggies. One of the options is to switch low carb diet periodically back to balanced healthy diet with calorie counting. You would be amazed how easier it is to go to calorie controlled diet after low carb schedule. All of the crazy food cravings suddenly disappear after few days of low carb diet. If you decide to go this route, try to find a food combination with steady weight loss and just stick with that combination as long as you can.
The other option is something that I discovered by accident, and I call it Rotating Diet Days.
I came to the idea of Rotating Diet Days by accident when I switched from low carb diet to eating plenty of fruits and vegetables. To my surprise, switching from proteins only to FRESH fruits only days was not only not detrimental, but in fact had rather weight loss enhancing effect. And what I liked the most, is that we are talking about really liberal amount of fruits. Eventually I found out that eating fresh non starchy vegetables alternating with fresh fruit or fresh fruit and fresh vegetable days is Ok as well. How much better could it get? We have a choice of a very effective and simple low carb diet that we can alternate with completely opposite fruit days or vegetable days and continue to lose or maintain the weight. We have more than three diverse and almost unlimited food diets following which you would not need to count calories and only pay attention to what you eat as instructed. Is it too good to be true? I have to say from the beginning that unlimited for some people is too literal. They are may be almost unlimited. And combining of such diets with reasonable calorie counting or at least a rough estimate would provide the best results.
I suggest to start with low carb diet and stick with it as long as you can, it is still one of the most weight loss effective and appetite normalising diets, when you fed up with it, then switch to either calorie restricted healthy diet or fruit days alternating with vegetable days and with and fruits and vegetable days. Eventually you may just rotate at your will whenever you want to go with any of these days depending on your cravings or other variables or switch them with regular healthy balanced diet days.
Low carb days
The main food on these days is meat or meat substitute (fish, seafood, eggs etc.). It is the most effective regimen for weight loss. You may have as many of those days in a row as you enjoy or tolerate when you feel that you need to lose few more pounds. For maximal weight loss benefit I recommend to put at least three or more of such days in a row. See the "Proteins" section for more explanations. Same principles apply as in low carb diet but it lasts less than a week. If you stay in this regimen for less than 3 days, your body might not switch into ketotic stay. Some reasonable portion control is needed, I would suggest to limit lean protein portions to no more than three palm size portions, or one medium chicken without skin and without fat a day. The major part of your daily meals is comprised of meat and fish. Combine proteins with high fiber vegetables (mostly leaves and stems). Eat fish, meat, eggs and low carb dairy. Limit carbs from any sources. You might have some healthy fats on low carbs days. Read carb counting. No fruits on low carb days.
Fruits days
FRESH Fruit days ideally should be limited to one to two days a week, alternating with other days. People with diabetes please discuss with your doctor first. On these days you should not eat any fats. In return you might have practically unlimited FRESH fruits to satisfy your sweet tooth that was craving for carbs during the low carbs days. You could have some fresh veggies (other than grains, legumes or starchy potato like food) with fruits without significant weight gain penalty. As long as you stay away from fats, the amount of fruits on these days may be close to unlimited, but it is possible to overdo with fruits. I would target around 1 kg of mixed fruits. I often go with an average size watermelon and some other fruits in between, I would rarely finish the whole watermelon. Also, if you decide to do two days in a raw the next day may not result in any additional weight loss, I think somehow our body gets more efficient in utilising fruits energy.
Melons are the best. Try to target to have up to one watermelon with some other fruits on this day. No bananas.
Berries are the next best. Caution with very sweet and tropical fruits like persimmons, avoid bananas, also be cautious with grapes, ripe pears, apples are Ok but in moderation.
Cheating with bad carbs on these days would not be as detrimental for weight loss as it would be on low-carb days. Diabetics should discuss with a doctor first and introduce fruits slowly while monitoring their blood sugars. Fructose in general does not affects blood sugar significantly as it is metabolised by liver only (see my Fruits section for more details), but many fruits have glucose and sucrose which might spike blood sugars significantly. If you are not sure - check the glycemic index.
Juices or preserved fruits other than frozen are not fruits, avoid them. Excessive fruit diets are controversial. There is also a potential link between an excessive fructose consumption and nonalcoholic fatty liver disease, since fructose is metabolised by liver only, which converts it into fat. There are also some controversial theories about excessive fructose consumption and Gout. I am not aware of any studies linking the fresh fruit consumption to such, most concerns are about fructose as a part of added sugars.
Vegetable days
Liberal preferably FRESH vegetables, preferably leafy and green veggies, while restricting fats and proteins, since most of the energy on these days should arrive from complex carbohydrates. This diet approaches closer than low carb diet to the healthy balanced diet concept. My version of vegetable days is somewhat similar to Paleo Diet except that I do not believe that dairy products need to be avoided completely. You may have as many of such days in a row as you enjoy. Ideally those days to be coordinated with calorie counting, but if you stay away from fats, grains, legumes, potatoes and starches, the amount vegetables, especially leafy ones, might be close to unlimited. It might be difficult under such scenario to overdo the 1500 calories threshold. Very minimal added fats on those days, mostly from dressings and protein containing food. Most of the energy should come mostly from carbs and lean proteins. Consider restrict or avoid legumes, grains and cooked root vegetables for maximal weight loss benefit. May have some FRESH or frozen fruits included on these days. May include lean meats, lean fish, eggs, seafood and other proteins roughly one-two palm size a day. Avoid fatty proteins and fats in general on those days. The amount of leafy veggies could be literally unlimited, but mind the dressings and other salad additives. Seed bearing parts of plants might be high in calories and should not be unlimited. Theoretically cooked vegetables could be Ok, but it might require consideration about calorie counting. I would avoid any cooked root vegetables and control or restrict cooked seed bearing parts of vegetables. Cooked vegetables are digested and absorbed better, they often might have added fats, the concept of unlimited might be not as realistic as with fresh veggies. Fruits should be either fresh or frozen. I would advise to avoid any cooked, processed or preserved fruits.
Fruits and vegetables days
Just combine the two of the above. Fats should be limited. Again, FRESH only both fruits and vegetables. Frozen fruits and veggies are Ok, but absolutely no cooked or processed/preserved fruits, I would stay away as much as possible from preserved veggies as well.
At the end you might have four types of relatively liberal close to unlimited food diets - low carb days, vegetable days, fruit days and vegetable and fruit days. You have to watch the scale, and if you gain weight on any of these regimens, you might be taking definition "liberal" too literally, and some limits might need to be set. Combining these days with calorie counting would maximize the weight loss results, but if you follow the restriction as described, you will find it difficult to overdo on calories.
Balanced diet
Balanced diet it is not a diet but a healthy balanced nutrition. It could take a book to describe different opinions, but my short version is: liberal fibrous veggies 5 cups/day, Fruits 2 cups/day. Watch for grains, legumes and root vegetables Healthy fats and nuts in moderation. Moderate dairy. Proteins portions should be around one-two palm size/day. Avoid red and processed meats. Poultry and fish are preferable. For weight maintenance try to target around 2000-2500 calories a day. For weight loss purposes try to stay under 1500 calories a day. UpToDate Link.
P.S.
The rotating diet days are somewhat similar to "carb cycling" approach used by many body builders to lose extra body fat. The main principle of carb cycling is having a calorie controlled diet with alternating low, medium and high carb days. The idea of those diets is to have a steady high amount of proteins, but on low carb days there are more healthy fats introduced as a source of energy. On high carb days the fats are limited and more energy comes from carbs. The calculations are complex. I think that my approach of carb cycling is much easier to implement and follow, but carb cycling certainly could be an option for a dedicated person.
Carb cycling approach is different than a theory of Dr. Hay developed in the beginning of the last century. He mistakenly felt that proteins and carbs should not be combined together in the same meal because of different acidity and alkaline properties.. At one point his diet was extremely popular and still has some followers too. Subsequent studies did not confirm that his theory has any benefits or scientific grounds, but who knows.