Kilo-calories (Calories with a capital C) are units of energy.
Humans use Calories for energy.
Calories come from the foods we eat.
Fat = 9 calories per gram
Carbohydrate = 4 calories per gram
Protein = 4 calories per gram
Fat is the most energy dense macronutrient, more than double carbs and protein.
Calories In, Calories Out
You take Calories in through food intake, and you burn or expend calories through daily living, exercise, digestion, etc.
Influencing body composition starts with measuring your Total Daily Energy Expenditure (TDEE).
This is the total number of calories you expend during daily living.
Use this calculator here to determine this.
This will influence how many calories you need to consume (Total Daily Energy Intake).
Maintenance is total daily calories to maintain weight.
Deficit is taking in less calories than you expend, and weight loss (hopefully from fat) occurs.
Surplus is taking in more calories than you expend, weight gain occurs.
Macronutrient Ratios and Putting Together a Diet Plan
Let’s say you weigh 180 lbs.
Around 1 gram per pound of bodyweight is recommended for athletes.
That’s 180 grams of protein per day.
That means 720 of your calories are accounted for.
Let’s pretend You need 2,269 Calories/day to maintain your weight (based on totals from the calorie calculator)
You need 2,769 Calories/day to gain around 1 lb per week.
To gain muscle (although a tiny bit of fat will come along with it), we want to be between these two.
2,500 Calories is our hypothetical calorie goal then. Go above this and we’ll get too fat.
So 2,500 – 720 = 1780 which needs to come from carbs and fats.
Considering our ratio, we need 1080 cals from carbs or 270 grams of carbs.
Then we need 720 cals form fats so about 80 grams of fat.
So our macro ratios look like: 80 grams fat, 270 grams of carbs, and 180 grams of protein (although you may need to play around with these a bit based on individual needs). This is a 30/40/30 fat/carbs/protein ratio, and is nice and balanced.
To lose weight (mostly fat), you would go a small amount under maintenance, and achieve this by lowering carbs and fats (keep protein steady) just a touch. In this case, ideally you would cut out about 10 grams of fat (90 calories), and 40 grams of carbs (160 Calories) for a total of 250 calories, bringing us down to 2,250 Calories and just under maintenance to lose very slowly and preserve lean mass.
Things to Consider
Slow is best. Do not try to gain or lose too fast. This will lead to excess fat gain or lean muscle loss. Keep a small surplus or a small deficit for best results. Aim to lose around 0.5 – 1% of your bodyweight each week.
Don’t stay in a deficit or surplus for too long. Constantly dieting will lead to exhaustion, imbalances in nutrients and possibly hormone disruption. On the flipside, constantly overeating will lead to obesity and higher incidence of disease.
Don’t cut out or spike a macro to gain or lose weight. Keep your macronutrient ratio balanced for best results and optimal nutrient intake.
Use a calorie calculator app to record dietary intake and Calories. This is really the only way to be precise about it and make sure you’re on the right track. Use an app such as myfitnesspal.
For more info, see this post: Planning Meal Frequency and Using Correct Macro-nutrient Ratios for Leanness, Size, and Strength