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Optimal Weight Loss Duration and Amount! Defying Fate with the Truth

"Good grief..." When it comes to bodybuilding, the goal of weight loss is to reduce body fat while maintaining muscle mass. Knowing the optimal duration and amount for weight loss is the first step to success. Here, we uncover the truth and provide effective weight loss strategies.

A dynamic illustration of a character inspired by Jolyne Cujoh from JoJo's Bizarre Adventure, standing in her iconic JoJo pose. She has long, light green hair styled in two buns with loose strands and wears a green patterned outfit. She stands fiercely, with her body twisted and one arm outstretched while the other rests on her hip. Surrounding her are stylized symbols of calories, fat molecules, and protein structures. The background features swirling energy and glowing elements, symbolizing the battle against fat and the maintenance of muscle. English onomatopoeia like 'ORA ORA' and 'MENACING' add to the intense atmosphere. The scene is vibrant, colorful, and dramatic, capturing the essence of a JoJo-style confrontation.

Weight Loss Duration and Amount

According to literature, the optimal weight loss duration should not exceed 8 weeks. Within these 8 weeks, a safe and achievable weight loss is 5-10% of total body weight. For example, if you weigh 80 kg, the ideal weight loss would be 4-8 kg over 8 weeks. This equates to a weekly weight loss of 500-1000 grams.

Calorie Intake Calculation

Relationship Between Body Fat and Calories

Body fat contains 7200 kcal per 1000 grams. To lose 500-1000 grams of body fat per week, the following calculations are necessary:

  • 80 kg × 5-10% = 4000-8000 g (weight loss over 8 weeks)

  • 4000-8000 g ÷ 8 weeks = 500-1000 g (weekly fat loss)

  • 500-1000 g / 1000 × 7200 kcal = 3600-7200 kcal (weekly calorie deficit)

  • 3600-7200 kcal ÷ 7 days = 514-1029 kcal (daily calorie deficit)

Calculating Caloric Expenditure

Caloric expenditure can be calculated using the formula: "Caloric Expenditure = Basal Metabolic Rate (BMR) × Activity Level Index". BMR is calculated by multiplying lean body mass by 30. The activity level index varies: for intense exercise (1 hour/day), it is 1.9; for rest days, it is 1.3.

Example for someone training 5 days a week and resting 2 days:

Activity Level Index = (1.9 × 5 + 1.3 × 2) ÷ 7 ≒ 1.73

Caloric Expenditure = Lean Body Mass × 30 × 1.73 = Lean Body Mass × 51.9

For an individual weighing 80 kg with 20% body fat, the lean body mass is 64 kg, resulting in a daily caloric expenditure of 3322 kcal.

Calculating Caloric Intake

If this individual aims to lose 10% of their weight over 8 weeks:

Caloric Expenditure 3322 kcal - Daily Calorie Deficit 1029 kcal = 2293 kcal (daily caloric intake)

Assuming only body fat is lost, the lean body mass remains 64 kg, and the weight becomes 72 kg, resulting in a body fat percentage of 11%.

Diet Composition


Protein intake is crucial during weight loss. When total calorie intake decreases, gluconeogenesis occurs, where amino acids are converted to energy. To prevent muscle breakdown, the proportion of protein in the diet should be higher. Additionally, protein has a high thermic effect (DIT) of 30%, meaning that a significant portion of its calories is used for digestion and absorption, increasing overall calorie expenditure.



The optimal weight loss duration is 8 weeks, with a target of losing 5-10% of body weight. Proper calorie calculation and protein intake can help maintain muscle while losing fat. "Good grief... but now we see a way to defy fate!"


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