Weight loss is not a moral problem. It is an energy problem. Eat less energy than you burn over enough weeks and weight comes down. Eat more and it goes up. The difficulty is not the math; it is living inside the math without feeling miserable.
Find your rough daily burn
Start with basal metabolic rate — roughly what your body spends staying alive. The Mifflin-St Jeor equation is a standard estimate: ten times your weight in kilograms, plus 6.25 times your height in centimetres, minus five times your age, plus five for men or minus 161 for women.
Then multiply by an activity factor: 1.2 if you sit most of the day, 1.375 for light activity, 1.55 for moderate training, 1.725 for hard training most days, 1.9 for physical work plus hard training. The result is an estimate of maintenance calories. It is a starting point, not a verdict.
The calorie calculator on this site does the arithmetic and shows a −15% target, a maintenance target, and a +10% target. Estimates only — a coach and a two-week weigh-in trend beat any formula.
Take 15 percent, not 50
A deficit of about 15% below maintenance is a sensible start for most people. If you maintain on 2,600 calories, that is roughly 2,200. It is enough to produce change and small enough that you are not starving by Thursday.
Bigger deficits produce faster scale movement and worse adherence. The best deficit is the one you can hold for twelve weeks. If you are constantly thinking about food, sleeping badly, and training like a wet towel, the deficit is too aggressive.
Protein is the lever
Aim for roughly 0.7 to 1 gram of protein per pound of bodyweight per day. For a 180-pound person that is 126 to 180 grams. Spread it across meals; a palm-sized portion at each meal is a decent visual anchor. Protein keeps you full and helps protect muscle while you lose fat.
Fill the rest with food you actually like. Rice, potatoes, bread, fruit, and vegetables are not the enemy. Fat is calorie-dense, so measure oil and butter if you are stuck. Liquid calories are easy to forget, so count them honestly.
The scale is a noisy instrument
Your weight moves with salt, carbohydrate, hydration, hormones, and how recently you used the bathroom. Day-to-day changes mean almost nothing. Weigh yourself under the same conditions most mornings, write it down, and compare weekly averages.
A loss of roughly half a pound to one pound per week is a reasonable pace for most people. If the four-week average is flat and you are honestly tracking, reduce by another 100–150 calories or add a little movement. If you are losing faster than a pound and a half a week for several weeks, eat a bit more.
Train to keep the muscle
A calorie deficit without strength training tends to cost muscle along with fat. Coached strength work gives your body a reason to keep the muscle while the fat comes off. It also gives you something to improve at that is not the scale.
At The Dungeon, weight loss is one of the three listed specialties, and the training is coached. Bring your calorie estimate to the coach and ask how the training should change as the weight comes down. That is a better conversation than guessing alone.
Good group of people.
Last thing: if you have a medical condition, are pregnant, or have a history of disordered eating, talk to a doctor or dietitian before running a deficit. A calculator is a tool, not a clinician.