If you are looking for a way to lose weight quickly, perhaps the paleo diet is for you: it is a low-carb, higher-fat diet, whose macronutrient breakdowns range from that typical of the Zone diet (40 carbs, 30 protein and 30 percent fat) to that of the ketogenic diet (over 60 percent fat, thirty percent protein and ten percent carbohydrates).

There are no portions to weigh, but there are only foods to prefer and foods to avoid. 

Among the foods to be preferred we find meat (from organic farming, only forage farming and not cereals, game), especially for the fatty parts and not only for the muscles; vegetables and fruit; sweet potatoes and some types of tubers but not traditional potatoes; fish, especially oily fish, and not canned (exceptionally you can eat dehydrated fruit); coconut; oil seeds and oil fruit; extra virgin olive oil in moderation and olives; coconut oil for seasoning, eggs, spices and herbs. It cannot be sweetened except with stevia or at least a little honey or malt or coconut palm sugar. You cannot drink alcohol. You can drink almond milk, coconut water, homemade and unsweetened coconut drinks. 

You cannot eat: cereals and legumes, including peanuts, soy and green beans, milk and derivatives, sugars, too sugary fruit.
In theory, fruit consumption should be limited, for example if you can eat it for breakfast. This is because the paleo diet is basically a low glycemic index diet that turns to ketogenic (higher fat consumption).