Calorie Surplus vs. Deficit: How to Bulk or Cut Smartly

The two phases of body composition change are bulking (gaining weight) and cutting (losing fat). Both require understanding your TDEE (Total Daily Energy Expenditure) and adjusting calories accordingly. Done right, you gain muscle with minimal fat. Done wrong, you gain 20 lbs of fat in a "bulk" or lose muscle in a "cut."

Step 1: Calculate Your TDEE

Your TDEE is how many calories you burn in a day including exercise. It's your maintenance level — eat this many calories and your weight stays the same.

The Mifflin-St. Jeor equation is the most validated:

Men: 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5
Women: 10 x weight(kg) + 6.25 x height(cm) - 5 x age - 161
Multiply by your activity factor (1.2 to 1.9)

Calculate Your TDEE →

Step 2: Choose Your Direction

Bulking (Caloric Surplus):

Add 200-400 calories above maintenance. This produces ~0.25-0.5 lbs of weight gain per week. Slow enough that most of it is muscle, not fat.

"Dirty bulking" is a waste of time. Eating 1,000+ calories above maintenance produces rapid weight gain, but most of it is fat. Cutting that fat off later takes months and risks losing the muscle you gained. A lean bulk is more efficient in the long run.

Cutting (Caloric Deficit):

Subtract 300-500 calories below maintenance. This produces ~0.5-1 lb of weight loss per week. The key is staying in a moderate deficit so your body burns fat, not muscle.

Recomposition (Simultaneous muscle gain and fat loss):

Beginners and people returning to training after a break can gain muscle and lose fat simultaneously by eating at maintenance calories with high protein. This is the "newbie gains" phase that makes everything else simpler.

Step 3: Set Your Macros

Goal	Protein	Fat	Carbs
Bulking	0.8-1.0g/lb	0.3-0.4g/lb	Fill the rest
Cutting	1.0-1.2g/lb	0.3-0.4g/lb	Fill the rest
Recomp	0.8-1.0g/lb	0.3-0.4g/lb	Fill the rest

Why high protein during a cut? Higher protein preserves muscle mass in a calorie deficit. It also has the highest thermic effect of food (20-30% of protein calories are burned in digestion vs. 5-10% for carbs and 0-3% for fats).

Get Your Macro Split →

Step 4: Track and Adjust

Weigh yourself daily (same time, same conditions) and track the 7-day average
If the 7-day average isn't moving in the right direction after 2 weeks, adjust by 100-200 calories
Reassess your TDEE every 4-6 weeks (as you lose/gain weight, your maintenance changes)

The scale is your feedback loop. You don't need a food scale or MyFitnessPal to track every calorie. If you know roughly how much you eat and the scale is moving in the right direction, you're winning. Track food more carefully only if the scale stalls for 2+ weeks.

Bottom Line

Bulk in a 200-400 calorie surplus. Cut in a 300-500 calorie deficit. Keep protein high (0.8-1.2g/lb). Track your weight trend weekly and adjust. The math is simple — the hard part is consistency.