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Calculating Calorie & Macronutrient Needs for Strength Training

nutrition, trainingTheo Brenner-RoachComment
Calculating calorie and macro needs for strength training header

When it comes to changing your weight, and improving your body composition you must pay attention to your caloric needs and macronutrient breakdown.

It is these 2 factors in conjunction with a progressive strength training plan that will bring about the changes you want. However, it’s not always easy to sift through the sheer amount of information available to find out exactly what you need to know.

So, if you’ve been left second guessing what exactly calories and macros are, why you need them and how to figure it all out, you’re in the right place.

What Are Calories & Why Do You Need Them?

Calories are the energy currency your body uses to function.

Whether you’re at rest, work or play your body is constantly using calories to provide itself with the energy it needs to not only perform but also survive. Calories are used to keep your heart beating, lungs breathing and brain thinking. Without sufficient calories your body would cease to function.

When you exercise or workout your calorie (or energy) output is increased in order to allow your body to perform the tasks you require of it. If your calorie input is higher than its output you will gain weight and if your input is lower than your output you will lose weight.

This change in energy is called the energy balance equation.

The energy balance equation is the relationship between the calories you put into your body through food/drink and the calories you expend through maintaining homeostasis and any exercise or activity you perform.

The energy balance has 3 basic rules:

  1. You will gain weight if your energy input is greater than your energy output
  2. You will lose weight if your energy input is less than your energy output
  3. You will neither gain nor lose weight if your energy input is equal to your energy output

Your overall daily calorie needs are made up from a few different functions which explains the differences in calories needs from one person to the next.

Basal Metabolic & Resting Metabolic Rate

Basal metabolic rate (BMR) is the number of calories you need at rest to allow your body to function at its most basic level. This term, BMR is often used interchangeably with resting metabolic rate (RMR) and makes up the largest part of your daily calorie needs.

The Thermic Effect of Food

In addition to your BMR there is also the thermic effect of food, which is the technical way of saying, the calories your body uses to digest the food you eat. This process accounts for a small portion of your daily calorie expenditure.

Non-Exercise Activity Thermogenesis

When trying to calculate your daily calorie needs you also need to account for Non-Exercise Activity Thermogenesis (NEAT). This is essentially all the activity you do which is not related to sleeping, eating or exercising and relates to the type of job you work, how much you move during the day, housework and how fidgety you are. (1)

It can account for a large amount of additional calorie output daily and explains why some people struggle to put on weight even eating whatever they want and vice versa.

Total Daily Energy Expenditure

TDEE for short, is the total amount of calories you expend each day, inclusive of the above and any exercise you do i.e. playing sports or resistance training.

How Do You Calculate Your Daily Calorie Needs?

Considering all of the above the simplest way to calculate your calories need is to use the following calculations:

  • Fat Loss = Bodyweight in lbs x 12
  • Maintenance = Bodyweight in lbs x 14
  • Muscle Building = Bodyweight in lbs x 16

These calculations will give you a good starting point but you may find you’re not quite hitting your sweet spot for optimal weight gain or loss.

What Is The Optimal Rate Of Weight Loss Or Gain?

Aim to lose weight at a rate of 1 – 2 lbs a week for optimal fat loss and muscle retention and aim to gain weight at a rate of 0.5 – 1 lbs a week for optimal muscle gain and minimal fat gain.

From here you can track your progress by weighing yourself daily and taking a weekly average. If you’re losing weight too quickly, not quickly enough or gaining weight too quickly or not quickly enough then you can either:

  • Add 100kcals (25g of carbs)
  • Remove 100kcals (25g of carbs)

Then track your weight again to see if it fixes the problem. Keep using this tactic until you hit your sweet spot.

What Are Macronutrients & Why Do You Need Them?

Macronutrients, also known as macros for short, are the 3 primary sources of calories.

Even if you are new to the term macronutrients you will undoubtedly be aware of the macros by their individual names, protein, carbohydrates and fats. Each macro plays a specific role in the body and provides a number of calories per gram.

  • Protein has 4 calories per gram
  • Fat has 9 calories per gram
  • Carbohydrate has 4 calories per gram

Knowing the number of calories provided by each macronutrient allows you to effectively meet your daily calorie needs. To determine how much of each macronutrient you need in your diet you first need to understand the roles they play in your body once they’ve been eaten.

Protein

Protein is very important and is used to break down and rebuild the cells in your body. This process is called protein synthesis and is vital for growth and maintenance of your body. When you eat protein, it’s broken down into amino acids by your digestive system in order to be used.

In total, there are 20 amino acids, 9 of these amino acids are called essential which means your body cannot produce enough of them and you must get them from food sources. The remaining 11 are called non-essential as the body can produce them in high enough quantities that it’s not essential that you get them in your diet.

Overall, protein plays an important role in building, repairing and regenerating your body’s tissues and cells. It helps in the preservation of muscle mass, immune function and aids in the production of essential hormones and enzymes. It’s particularly important if you exercise regularly (more on this later).

Fat

Fat in the diet allows you to absorb fat-soluble vitamins, provide essential fatty acids and in some circumstances, provide a source of energy.

When eaten, fat is broken down into fatty acids (mostly in the small intestine) to be used by the body and depending on total calorie intake fat is commonly stored for future use, which can lead to the accumulation of body fat and weight gain. Fat is vital for the absorption of fat-soluble vitamins, maintenance of cell membranes and hormone production. It can also be used as energy by the body and as insulation to help maintain a normal core body temperature.

Carbohydrate

Carbohydrate can be metabolised by the body very quickly and is your preferred source of energy.

When you eat carbohydrates, they get broken down into glucose to provide energy to your body. Any glucose not used is converted into glycogen and stored in your muscles and liver for future use. Your liver can store approximately 100g of glycogen which is used to maintain blood glucose levels between meals. Whereas, your muscles can typically store 400 – 500g of glycogen which is used to provide movement.

Carbohydrates aids in the proper function of your heart, brain, kidneys and muscles. It is also important for intestinal health and digestion.

Macronutrients & Resistance Training

Let’s look at how this now relates to strength training and how regular strength training influences your macronutrient needs.

How Much Protein Do You Need?

The topic of how much protein you need daily to build or preserve muscle mass is the subject of great debate in the fitness industry. Depending where you look the amounts can vary greatly and it can be difficult to know what to do. The general consensus is that your intake should be a slightly higher when eating in a calorie deficit to help preserve muscle mass and slightly lower for maintenance or muscle building.

But what is this amount?

Well research (2) shows that a protein intake between 0.6 – 0.9 g per lb of bodyweight is adequate for maximising protein synthesis. This same study also recommends that eating closer the 0.9 g per lb mark may be advantageous for those eating in calorie deficit to help preserve muscle mass.

Another study (3) found that 0.8g per lb of bodyweight is the optimal daily intake to promote muscle growth in those who perform regular strength training. The researchers of this study also noted that those who perform endurance as opposed to strength can get away with as little as 0.5 – 0.6 g per lb of bodyweight.

Finally, one study (4) concluded that their results were “unable to show any significant evidence indicating that protein intakes above 2.0 g per kg per day [was effective] for enhancing strength and body composition changes in college strength/power athletes.”

This study in particular highlights the fact protein intake above 1g per lb of bodyweight is not necessary for the recreational to semi-serious weightlifter, given that even under the physical demands of their training college strength and power athletes gained no additional benefits from a protein intake over 2g per kg which is the equivalent to 0.9g per lb.

The bottom line

Optimal protein intake to build or preserve muscle mass is 0.6 – 0.9 g per lb of bodyweight, with the idea of sticking closer to 0.9 when eating in a calorie deficit and closer to 0.6 when eating in a calorie surplus.

How Much Carbohydrate Do You Need?

There is a lot of controversy surrounding carbohydrate intake, particularly in relation to fat intake BUT when it comes to intense resistance training you can’t go wrong with a moderate to high carbohydrate intake.

Let me show you why.

Research (6) shows that glycogen stored in your muscles is the primary fuel source of moderate to intense exercise. Add to this research (7) that shows a sufficient carbohydrate intake that keeps your muscle and liver glycogen stores full can improve workout performance.

Not only this but research (8, 9) shows that when compared a low carbohydrate intake (approx. 220 g per day) against a high carbohydrate intake (approx. 350 g per day) resulted in more strength lost, slower recovery and lower levels of protein synthesis.

Regardless of whether you’re trying to lose fat and preserve muscle mass or gain muscle and minimise fat gain you can begin to see why a moderate to high carbohydrate intake is beneficial for you if you’re strength training regularly.

How much carbohydrate is enough?

As the answer will vary depending on your goal, starting weight and protein intake the best way to calculate your carbohydrate intake is to first allocate your protein and fat intake and then use all remaining calories from your daily allowance for carbs.

How Much Fat Do You Need?

Fat is an essential part of your diet but it is also the most calorie dense of the 3 macronutrients. 

There are some fats (omega-3 & omega-6) that you need as an essential part of our diet that your body cannot produce and you need to obtain from food. There is no doubt you need to include fat as part of your daily calorie intake, however, when training regularly and eating to maximise your results you’d be smart to eat enough fat to support overall health but not so much that you can’t maximise your carbohydrate intake.

How do you know how much fat this is?

The general recommendation and one I’ve used and given myself is to have approximately 30% of your daily calorie intake made up from fat and for the most part, this is a solid strategy. However, depending on your daily calorie needs, making 30% of your daily calorie intake up from fat can lead to an unnecessarily high fat intake.

When this is the case, a recommendation of 15 – 20% of your daily calorie intake from fat is proposed. Ultimately, provided you get at least 0.3 g of fat per lb of fat-free mass you’ll be eating enough to maintain health. (10)

Macronutrient Recommendations For Strength Training

Based on personal experience, the experience of clients and the research available my macronutrient recommendations are as follows:

  • Protein = 0.6 – 0.9 g per lb of bodyweight*
  • Fat = 15 – 30% of daily calorie intake
  • Carbs = remainder of daily calorie intake

*higher when in a calorie deficit and lower when in a calorie surplus

However, I understand everyone is different and not everyone has the same goals so there will of course be differences of opinion within the industry.

Ultimately, it comes down to what you can stick to long-term, if for you that means following my recommendations, awesome, but if that means lower carb and higher fat then that’s ok too.

What’s More Important, Calories or Macros?

There’s no arguing that calories and macros are heavily intertwined but a good way to think of the difference is like this.

  • Calories are the main factor in weight change i.e. will you lose or gain weight
  • Macros as the main factor in body composition i.e. will you lose fat or muscle or gain fat or muscle.

As for what’s more important, it really depends on your goal:

1. Weight change with not too much concern about body composition

If this describes your goal then aim to hit your total calorie goal within 100 kcals either side and you’ll be fine. You’ll change your weight at a steady pace and your daily calories will balance out over the week.

2. Weight change with the primary purpose to improve body composition

If this describes your goal then aim to hit your macronutrients within 5 – 10g and this by default will keep you close to your calorie goal. Whilst also allowing you the benefits of the a well-structured macronutrient breakdown.

Summing Up

A practical guide on understanding and calculating your calorie and macro needs when strength training for optimal results.