Using our free flexible diet calculator, you can easily determine how many macros your body needs to reach your goal. Enter your details below and we'll tell you how much fat, protein and carbohydrates you should eat!
Macronutrients (macros) are the three core nutrients which your body gets its energy from. They're also the three nutrients you consume the most of, every day. Protein, Fat, and Carbohydrates (Carbs) are all very important for your body to remain fit and healthy. Our macro calculator looks at your lifestyle and determines how many calories and how much fat, protein and carbs your body needs to reach your goal.
A macro calculator is a great way to easily estimate how many macros your body needs. We use multiple facets of your life; your age, height, weight, sex, and how active you are. We also ask you about your goal: you could want to lose fat, maintain your weight or bulk up.
The calculator uses the Mifflin St Jeor Equation to determine your Basal Metabolic Rate (BMR). Your BMR is important because it is the rate of energy you burn over time, at rest. Basically, it's how many calories you need to survive, if you sat on the couch all day and did literally nothing. The calculator then multiplies that value by how active you are to determine your Total Daily Energy Expenditure (TDEE), which is how many calories you need to maintain your current weight, with how active you currently are.
Even though they're similar, and your macro calculation comes from calories, they're quite different. Just focusing on how many calories your body needs means you're not paying attention to the makeup of your food; how much fat, protein, and carbs you're ingesting. For example, if you're eating 1600 calories a day, you could easily have a diet that's heavy on fat and carbs, while not getting enough protein to promote muscle and tissue growth. Focusing on macros means you meet your calorie goal while ensuring you get enough of each macronutrient to reach your own body goals.
Flexible dieting is built around the concept of eating what you want to eat, as long as you're providing your body with enough (and not too much!) nutrients. In order to know how much you should be eating, you need to know what macros your body needs. Once you know how much fat, protein, and carbs you need, you can start to make a meal plan that suits your flexible dieting. Even though meal plans add structure to your life, the flexibility comes from eating ice cream, burgers, and other food (nothing is off the table!). If you're interested in learning more about flexible dieting, we've written a beginners overview here.
Your body can burn fat by consuming fewer macros than you need to maintain your weight. The simple science is, if you're eating fewer calories than you need, your body will look to find energy from stores that already exist in your body.
Once we understand your TDEE, we can work out how many calories you need to eat to burn fat; which is usually around 80% of your Total Daily Energy Expenditure. There are other common diets like '1200 calories a day', but often people find that's not enough, and it can result in people binge eating and putting on weight after they 'finish' dieting.
How is losing weight different from losing fat? Often fad diets focus on losing water weight for instant results and dropping a lot of physical activity so you don't put on any muscle. If you develop muscle while dieting, you might see the scales stagnate, or even go up. There's a high chance you're still losing fat, but you're also putting weight on through muscle growth. Losing water weight might make you feel good when looking at the scales for a week or two, but water is incredibly important for the human body.
The calculator will automatically work out how many grams of each macronutrient your body needs to reach its goal. The National Health and Medical Research Council (Australian Government) has guidelines around recommended daily intake of macros for women and men in Australia:
Protein: 15 - 25% Fat: 20 - 35% Carbs: 45 - 65%
All macros have a healthy range, for protein it's 10%, fat is 15% and carbs is 20% which gives a lot of flexibility in your diet. For example, if you're maintaining weight, you might only want 18% protein intake, but if you're gaining muscle, you might want to up it to 25%, or even 30% (which has been approved by the NHMRC as not introducing adverse health issues).
So with the above guidelines, you can work out how many grams you need for each macronutrient to reach your goal. For example, if you require 1600 calories:
Protein is essential for building body mass and the critical building block for muscle growth and other tissue. Protein has 4 calories per gram. To find the lowest end of the range:
1600 calories * 0.15 (15%) = 240 calories
240 calories / 4 (calories per gram) = 60 grams of protein
The lower end of the fat range supports your body's ability to sustain weight, while the upper end of the range was set in relation to the risk of obesity. Some fats the body needs, but cannot make (like omega-3), fats can assist in the absorption of some vitamins (like vitamin A and vitamin D) and also makes food taste good! Fat has the most calories per gram out of the three macronutrients, at 9 calories per gram. To find the lowest end of the range:
1600 calories * 0.20 (20%) = 320 calories
320 calories / 9 (calories per gram) = ~35 grams of fat
Carbohydrates provide your body with most of the energy it needs, in the form of starches and sugars. Like protein, there's 4 calories per gram of carbs. To find the lowest end of the range:
1600 calories * 0.45 (45%) = 720 calories
720 calories / 4 (calories per gram) = ~180 grams of carbs
Having an understanding of how much energy your body needs, and what food it takes for you to provide your body with what it requires, is essential for you to eat healthy. Even if you're not interested in (or currently on) a flexible diet, once you know how many calories and what portion of macronutrients you need, you become much more conscious of what you're eating and how much of it you're consuming.