Weight Loss Calculator
Age
yrs
Weight
lbs
Height
ft
inch
Gender
Activity level
Weight goal
lbs
Diet duration
weeks
Diet type
Balanced
Carbs
50%
Proteins
20%
Fats
30%
Athlete
Carbs
60%
Proteins
15%
Fats
25%
Body Builder
Carbs
53%
Proteins
30%
Fats
17%
Custom
Carbs
50%
Protein
20%
Fats
30%
Results
Daily Caloric Intake
2000
Daily Macronutrient intake
Carbs
237g
Proteins
147g
Fats
40g
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Weight Management Explanation
Our bodies require energy for anything we do. Whether that is thinking or moving, we need fuel to initiate and maintain the process of doing work. We get this energy from nutrition in the form of food and drinks, measured in kilocalories (kcal). The kcal we require to maintain our body weight is called the Total Daily Energy Expenditure (TDEE) and reflects how much energy we expend/use in a day. Over time, if we consume more kcal than our TDEE, we gain weight. If we consume less kcal than our TDEE, we lose weight.
Practically all the kcal come from three different groups of food called macronutrients: carbohydrates, protein and fats1. Each have their essential role to play in maintaining a healthy body and mind. How much you should consume of these macronutrients depends on your lifestyle.
Whether you are interested in losing weight (cutting), gaining weight (bulking) or maintaining a healthy and balanced diet, this tool helps you calculate your macronutrient intake so that you can reach or maintain your desired weight.
1 Alcohol also provides calories, but is not nutritional. Hence, we leave it out of any further text. Be aware that alcohol provides more calories per gram consumed than carbohydrates and protein.
Weight Loss
Typically, people want to lose weight in the form of body fat tissue. As a rule of thumb, it is often cited that we need a deficit of about 7700 kcal to lose 1 kg of body fat (Wishnofsky, 1958). However, this value does not hold for everyone precisely. There are other factors that influence it, such as gender and body composition (Hall, 2008; Hall et al., 2012; Heymsfield et al., 2012). Also, the value, albeit presented as a constant, actually changes as the weight loss journey continues, partly because of your altered body composition. (Hall, 2008; Hall et al., 2012, Heymsfield et al., 2012). The number does not seem too far fetched, though, and is used in many applications as a simple method to perform calculations.We do feel that it is important to note that the deficit of 7700 kcal to lose 1 kg of fat tissue has come under some scrutiny and scientific debate. However, there is a delicate balance between accuracy and ease-of-use. For all intents and purposes we have decided to use the 7700 number in the calculator, since its accuracy appears to be sufficient for most applications. In the future we may add a more accurate, refined, but more complex way to calculate the macronutrients intake.
Diet Types
We have read the science and have selected three lifestyles for which to calculate your macronutrient intake: a balanced diet, a diet for athletes, and one for body builders. Most people will need to select the balanced diet type. Note that, especially in nutrition, research can be divided on some topics. The body is very complex and unique; a schema that works for every human being simply does not exist. Nonetheless, for the diet types we list below, we provide guidelines with numbers that are quite stable across the articles we have read.
All Diets
No matter your diet type, whole, unprocessed and varied food is always healthiest to eat as a base for your nutrition. Of course, eating refined foods from time to time is no issue, especially if you are about to engage in a high intensity exercise. Generally however, the importance of a whole, unprocessed and varied diet cannot be stressed enough.
Balanced Diet
For most people, a healthy diet consists of roughly 50% carbohydrates, 20% protein and 30% fats (Espinosa-Salas & Gonzalez-Arias, 2023; Institue of Medicine, 2005). This means that 50% of the kcal you take in should come from carbohydrates, 20% from protein and 30% from fats. How much that is to grams per day depends partly on your Total Daily Energy Expenditure (TDEE), amongst other factors. The TDEE is the energy in kcal we use in a day. During weight loss, or cutting, we need to eat less kcal than our TDEE. During weight gain, or bulking, we need to eat more than our TDEE.
Athletes
The athlete lifestyle is characterized by intense, long workouts, 5-6 times per week. Because of their intense workout routines, athletes have a very high energy expenditure and thus need to eat a lot to maintain a healthy weight. This means that an athlete's diet requires a relatively higher carbohydrate intake. Carbohydrates are a fast and efficient energy source, which is desired when engaging in high intensity exercise. Note that it is not recommended to go into **a** calorie-deficit when you are an athlete, as it may lead to physical and mental issues (Kerksick et al., 2018). Depending on how intense the athlete works out, the macronutrient balance can be somewhat variable. On average however, a recommended intake consists of 60% carbohydrates, 15% protein and 25% fats.
Body Builders
The body builder is focused on gaining muscle mass and losing body fat. Suffice to say, a body builder's diet consists of an elevated protein intake and a lower fat intake (Roberts et al., 2020; Lambert, Frank & Evans, 2004). Again, the exact numbers vary slightly, depending on gender and intensity of training. Note that, due to higher participation of males in the physical sports, most research has been conducted on male body builders and may be slightly biased. A macronutrient balance we found to be somewhat consistent for body builders is 53% carbohydrates, 30% protein and 17% fats.
Example - how much to eat of each macronutrient per day?
Daniel is a 27 year old male weighing 80 kilograms and is standing 170 cm tall. He has a slightly active lifestyle. He wants to weigh 75 kilograms within a period of 12 weeks (or 84 days). He opts to follow a balanced diet type, which consists of 50% carbohydrates, 20% protein and 30% fats. We know that both carbohydrates and proteins provides 4 kcal per gram, whereas fats provide 9 kcal per gram (Espinosa-Salas & Gonzalez-Arias, 2023). Using a handy Total Daily Energy Expenditure calculator, he finds out that to maintain his current body weight, he has to eat 2651 kcal per day.
Daniel wants to lose 80kg - 75kg = 5kg of fat tissue in a period of 12 weeks. As stated before under the Weight Loss section, a deficit of 7700 kcal is needed to lose 1kg of fat tissue. This means Daniel has to eat 7700kcal*5kg = 38500 kcal less in a period of 12 weeks. 12 weeks is 12*7 = 84 days. This means Daniel needs to eat 38500kcal/84days = 458 kcal per day less. Daniel has to eat 2651 kcal - 458 kcal = 2193 kcal per day over a period of 84 days.
Using a balanced diet type, 50% needs to come from carbohydrates, 20% from protein and 30% from fats. This corresponds to:
- 2193kcal*0.50 = 1096.5 kcal carbohydrates
- 2193kcal*0.20 = 438.6 kcal protein
- 2193kcal*0.30 = 657.9 kcal fats.
Carbohydrates and protein provide 4 kcal per gram and fats 9 kcal per gram. This means Daniel needs to eat:
- 1096.5kcal / 4kcal/gram = 274 grams of carbohydrates
- 438.6kcal / 4kcal/gram = 110 grams of protein
- 657.9kcal / 9kcal/gram = 73 grams of fats
for a period of 12 weeks to lose 5 kg of fat tissue.
References
- Espinosa-Salas, S., & Gonzalez-Arias, M. (2023). Nutrition: micronutrient intake, imbalances, and interventions. In StatPearls [Internet]. StatPearls Publishing.
- Hall, K. D., Sacks, G., Chandramohan, D., Chow, C. C., Wang, Y. C., Gortmaker, S. L., & Swinburn, B. A. (2011). Quantification of the effect of energy imbalance on bodyweight. The Lancet, 378(9793), 826-837.
- Hall, K. D. (2008). What is the required energy deficit per unit weight loss?. International journal of obesity, 32(3), 573-576.
- Heymsfield, S. B., Thomas, D., Martin, C. K., Redman, L. M., Strauss, B., Bosy-Westphal, A., ... & Nguyen, A. M. (2012). Energy content of weight loss: kinetic features during voluntary caloric restriction. Metabolism, 61(7), 937-943.
- Kerksick, C. M., Wilborn, C. D., Roberts, M. D., Smith-Ryan, A., Kleiner, S. M., Jäger, R., ... & Kreider, R. B. (2018). ISSN exercise & sports nutrition review update: research & recommendations. Journal of the international society of sports nutrition, 15(1), 38.
- Lambert, C. P., Frank, L. L., & Evans, W. J. (2004). Macronutrient considerations for the sport of bodybuilding. Sports Medicine, 34(5), 317-327.
- Roberts, B. M., Helms, E. R., Trexler, E. T., & Fitschen, P. J. (2020). Nutritional recommendations for physique athletes. Journal of human kinetics, 71, 79.
- Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, Subcommittee on Interpretation, Uses of Dietary Reference Intakes, Subcommittee on Upper Reference Levels of Nutrients, Panel on the Definition of Dietary Fiber, & Panel on Macronutrients. (2005). Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids. National Academies Press.
- Wishnofsky, M. (1958). Caloric equivalents of gained or lost weight.