The general rule of thumb is that if less energy (food) is taken in by the body than burned (exercise) there will be fat loss (and vice versa). Want to manage your weight? You just need to count calories right? Sounds easy.
I don't recommend it.
The truth is that using calorie counting as a way to manage diet and exercise is actually time consuming and difficult. Even if you are 100% on top of writing everything down you still won't be very likely to have it right because calorie counting is typically extremely inaccurate.
Food labels can have up to a 25% margin of error. That means it is almost impossible to know EXACTLY how many calories are going into our body. Even if you could, it is hard to know with mathematical certainty how much your body will use. There are many factors that go into how food is absorbed and used.
Each person reacts to and processes foods differently. We burn energy through the process of digestion but the health of the GI tract impacts how much of the total energy intake can actually be absorbed and put to work.
We also lose energy through excretion. How much is determined by another series of factors. This is already getting complicated and we haven’t even talked about exercise yet.
Chances are those of you who have tried calorie counting have been frustrated trying to figure out how many calories you are burning adding up all the little numbers in the charts of daily activities in books and online. It gives me a headache just thinking about it.
What can you do instead? Eat whole, minimally processed foods. Not many diets out there are going to tell you it is ok to eat all processed food. Focus on a macro balance with nutrient dense foods to avoid deficiencies.
Then learn the right strategies to get the right amount of food for you. Portion sizing can go a long way and you already have the right measuring tool with you. Your hands are already scaled to your size and make the perfect portioning equipment!
Your palm is equal to one serving of protein. Your fist? That's a serving of veggies! Your cupped hand is equal to a serving of dense carbs and your thumb can measure out a portion of fats. Serving totals can be adjusted from there based on hunger, fullness, preferences, goals, activity, and most importantly, results.
In the end there is no magical "best diet" but focusing on food awareness and quality is a proven technique to help people tune into their own hunger and appetite. You can learn to balance your energy in vs energy out without the ineffective (and annoying) calorie counting math.