If I want to lose weight I know that I have to eat 1200 calories. Is it really all about calories? Does macronutrient content have an impact on weightloss? For instance, if I eat 1200 calories and it's all fat will I still lose weight? So confuseddddd...

What made you pick 1200 calories as a number?

Your health is based on eating a balanced diet which means eating nutrients at a specific level / ratio.

Certain macronutrients at specific levels enhance the speed of weight loss.

You will not lose weight unless there is a calorie deficit.

It's yes and no. If you eat 1200 calories of fat you'll probably still lose weight. But while your body doesn't actually require carbs, and only needs a very small amount of 'essential fatty acids' to survive, it really does need protein, so that wouldn't exactly be good for your health

But macronutrients do matter. Don't get enough protein and you'll be more likely to lose muscle. Also, protein is slightly more calories to burn. I.e. if you eat 1800 calories with an emphasis on protein you'll probably lose more than with 1800 calories with an emphasis on carbs or fat.

As you start to get really lean macronutrient content can become even more important. I'm not that lean yet, so I don't know the details, but I've heard about the concept

A good rule of thumb is - eat as much protein in grams as your bodyweight in pounds. Try for around 30% fat, but go for the unsaturated kinds like avocado & olive oil if you can (this is for heart health, I don't think it matters for actual weight loss) and fill in the rest with whatever you want - green leafy vegetables and fruits etc.

Well if you consume 1200 of fat which is 9 calories per gram of fat then your would be consuming approximately 135 grams of fat. If this happens the weight loss may not be the most healthiest way to be losing weight. But yes if a calorie deficit is in play then you will lose weight.

Remember 1200 calories does not fall into the factor for everyone it depends it is based on you body.

I see from what you have posted elsewhere that your start weight is 144 pounds - aiming to drop to 128. I would set your calories at 1400 if I were you and maybe even slightly higher.

Most people will lose weight if they eat between 8 and 12 times their weight in pounds. This presumes a level of exercise and accurate logging of food and therefore counting of calories. Use FitDay - Free Weight Loss and Diet Journal.

It is best to incorporate regular exercise and start off with a higher level of calories. You will soon see whether you can lose weight at that level.

That gives more room to reduce things if the weight loss dries up. If you kick off with too low a number of calories you do not have any room to drop things when your body gets used to that.

This gives you more calories which you should use wisely to hone up your nutrition. This will give you the best rate of weight loss. It will also mean that as you get to goal you will need only a minor amendment to things to maintain your new rate on a really healthy diet.

We need all the nutrient food types. Carbs are contained in all the fruit and veg that you eat which provide you with the vitamins that protect you against disease. Different vitamins have been shown to protect against things like cancer... Fat is good for your skin. Calcium is good for your bones... I am being simplistic here but I am sure that you get the idea.

Everyone else has pretty much answered the question but I"ll just reiterate.

Yes, if you eat 1200 calories, you'll lose weight. At least at first. But if you don't make sure to eat HEALTHY calories (a good balance of complex carbs, proteins, and healthy fats), eventually your weight loss will stall because your body isn't getting sufficient nutrients. You can trigger the "starvation response" in your body even when you're getting sufficient calories by not getting proper nutrition.

So while yes, it is about calories, it's also about nutrition.

Now I get it! Thank you everyone!

Yes, macronutrient content has a very important impact on weight loss.

High glycemic index (GI) foods (grains, pasta, rice, potatoes, sugar, candy...) raise your insulin levels. Insulin is a fat storage hormone: it blocks existing fat from being burned for energy as well as instructing the body to store as much as possible of whatever was just eaten as fat. So, you can go into calorie deficit and still not lose weight at all if you keep eating high GI foods. You will feel like you are starving because you are: your body will be unable to access the vast reserves of fat for energy (to make up the balance of your calorie deficit).

On the other hand, if you eliminate high GI foods from your diet, your insulin levels will remain low after every meal. Low insulin levels allows the body to access stored fat for energy, and if you have a calorie deficit then this is exactly what will happen. You will burn fat without even trying, simply because your insulin is low after meals and your body needs more energy to operate as you are not eating enough. Stored fat will be used, just to have the energy to keep on breathing.

I lost 55 lbs without exercising at all, and without feeling hungry at all. I simply stopped eating high GI foods. I've only recently started exercising during the past month or two, now that I don't have so much to carry around...

The key to weight loss is managing your insulin. Or as they say "Abs are born in the kitchen, not the gym"... 80% correct food intake, 20% exercise, that's the approximate formula for the six-pack.

It seems most of what I wanted to say has been said.

If you are looking for a healthy balance in macro nutrients, then I'll suggest something like 40/30/30 for carbs/protein/fat. And remember that fat should come primarily from monounsaturated fats. That will help to keep all your meals healthy and give you the energy you need for regular exercise.

Also eating smaller meals more often seems to help.