Do macros matter more than calories or vice versa? If I don't eat enough protein I lose muscle. If I eat too many calories I gain weight. So what's optimal?
When body composition manipulation is the plan, then calories and macros are both incredibly important, but calories are definitely king.
Here's how it all works out:
Weight loss and weight gain are all functions of the energy balance equation; specifically, what is the difference between calories taken in and calories going out?
In a general sense, to lose weight, you want to consume fewer calories than you burn, and if you want to gain weight, you want to consume more calories than you burn. There is more nuance to it, especially when one is at the end of a hard diet and is trying to lose the last few pounds.
Macros are what help your body determine how much muscle mass will be spared or grown depending on if you're in a cut or a bulk diet.
- When you're dieting to lose weight, your protein intake starts to become significantly more important than your fat and carbohydrate intake. This is because protein consumption helps to mitigate muscle lost during a significant caloric deficit. While cutting weight, it's very beneficial to be eating anywhere from 1-2g of protein per pound of body weight, while also strength training. This will help to minimize muscle loss due to a caloric deficit.
- While you're trying to gain weight, carbohydrate intake becomes more important. Protein intake is still important and it should be kept around 1-1.5g per pound of body weight, but carbohydrate intake becomes more important as this is the primary driver for energy production during strength training/muscle building activities.
You'll probably have noticed that I haven't said anything about fat intake yet, and the reason for that is that (in my opinion) fat intake has little effect on weight gain or loss, specifically. That said, fat intake is still very important to monitor as it is a necessary component for healthy hormone production and overall health, so make sure to keep a decent number of calories from fat included in your diet. Don't avoid any specific types of fat (except for trans fats) and get a good mix of saturated, monounsaturated and polyunsaturated fats.
You will find that there are any number of approaches to dieting for weight loss, and very few for weight gain. However, whatever approach you take will be ineffective if you aren't prioritizing a caloric deficit or surplus, respectively. My suggestion is always to start with the smallest deficit or surplus necessary (100–200 calories for loss or 300–500 calories for gain per day) to illicit some change, and adjust as necessary from there.