Starting a calorie deficit means eating fewer calories than your body burns each day, and the simplest way to begin is by cutting roughly 500 calories from your current intake. That single change typically produces about half a pound to one pound of weight loss per week. But getting there without constant hunger or muscle loss takes a bit more planning than just eating less. Here’s how to set it up properly.
Estimate How Many Calories You Burn
Before you can eat below your maintenance level, you need a reasonable estimate of what that level is. Your body burns calories just to keep you alive (breathing, digesting, circulating blood), and then burns more through daily movement and exercise. The combination of these is your total daily energy expenditure, or TDEE.
The most widely recommended formula for estimating your baseline calorie burn is the Mifflin-St Jeor equation:
- Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
- Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161
This gives you your resting metabolic rate, the calories your body uses at complete rest. To get your TDEE, multiply that number by an activity factor: 1.2 if you’re mostly sedentary, 1.375 if you exercise lightly a few times a week, 1.55 for moderate exercise three to five days a week, and 1.725 if you’re very active most days. If math isn’t your thing, dozens of free online TDEE calculators will run the equation for you. Just know the result is an estimate, not a precise measurement. It’s a starting point you’ll adjust based on what actually happens on the scale.
Choose Your Deficit Size
A daily deficit of 500 calories is the standard recommendation for steady, sustainable fat loss. Harvard Health Publishing notes that a 500 to 1,000 calorie daily deficit, producing one to two pounds of loss per week, falls within the range experts consider safe. For most people, starting at 500 is the better move. A 1,000 calorie deficit can work for someone with a lot of weight to lose, but it’s aggressive enough that hunger, fatigue, and muscle loss become much harder to manage.
There are hard floors you shouldn’t drop below. Women should not eat fewer than 1,200 calories per day, and men should stay above 1,500, unless a healthcare provider is directly supervising. If your TDEE estimate minus 500 puts you below those thresholds, use a smaller deficit or increase your activity level to widen the gap from the other side.
Track Your Intake (At Least at First)
Most people dramatically underestimate how much they eat. Tracking food for even two or three weeks builds awareness that lasts long after you stop logging. Use a food tracking app, weigh portions with a kitchen scale when you can, and pay attention to cooking oils, sauces, and drinks, which are the most commonly missed calorie sources.
You don’t have to track forever. The goal is to learn what 500 calories of chicken and vegetables looks like versus 500 calories of granola, so you can eventually eyeball portions with reasonable accuracy. Many people cycle between periods of tracking and periods of intuitive eating once they’ve built that foundation.
Prioritize Protein
When you eat fewer calories than you burn, your body pulls energy from both fat stores and muscle tissue. The single most effective way to tip that ratio toward fat loss and away from muscle loss is eating enough protein. Current guidelines for preserving muscle during weight loss recommend roughly 0.7 to 1.0 grams of protein per pound of body weight daily. For a 170-pound person, that’s 119 to 170 grams per day.
That’s more protein than most people eat by default, so you’ll likely need to plan around it. Lean meats, fish, eggs, Greek yogurt, and legumes are all practical sources. Hitting your protein target also makes the deficit feel easier because protein is the most satiating macronutrient, keeping you fuller for longer on fewer calories.
Eat Foods That Keep You Full
Hunger is the main reason people abandon a calorie deficit. The workaround is choosing foods that take up a lot of space in your stomach relative to their calorie count. These tend to be high in protein, high in fiber, high in water content, and low in energy density, meaning they weigh a lot but don’t pack many calories per gram.
Boiled potatoes are a useful example. They have a much higher water content than rice or pasta, so you can eat a significantly larger portion for the same number of calories. That physical volume stretches your stomach and triggers fullness signals. Other reliably filling foods include eggs, oatmeal, fish, soups, lean meats, Greek yogurt, legumes, and even popcorn. Whole, unprocessed foods are generally more filling than their processed equivalents because they retain their fiber and water content.
A practical strategy: fill half your plate with vegetables or a broth-based soup, a quarter with a protein source, and a quarter with a starch or grain. This naturally produces meals that are large in volume but moderate in calories.
Use the Scale Correctly
Your body weight fluctuates by one to four pounds on any given day based on water retention, sodium intake, hormones, and how much food is sitting in your digestive tract. Weighing yourself once and reacting to that single number is misleading. Instead, weigh yourself at the same time each day (ideally first thing in the morning, after using the bathroom) and compare weekly averages. If your average weight trends downward over two to three weeks, your deficit is working.
If the scale hasn’t budged after three full weeks of consistent tracking, your calorie estimate is probably too high. Cut another 100 to 200 calories per day or add a bit more activity, then reassess after another two weeks.
Expect Your Body to Adapt
As you lose weight, your body burns fewer calories. This happens for straightforward reasons: a smaller body requires less energy to move and maintain. But there’s also a more aggressive adjustment called metabolic adaptation, where your calorie burn drops more than you’d expect from size alone. Weight loss actually reduces the size of several internal organs, including the heart, pancreas, and kidneys. Because organs burn calories at a rate up to 20 times higher than muscle tissue, even small reductions in organ size meaningfully lower your resting metabolic rate.
People with greater metabolic adaptation lose weight more slowly and often experience stronger increases in appetite. This is why weight loss feels progressively harder over time, not because you’re doing something wrong, but because your body is recalibrating. The practical response is to recalculate your TDEE every 10 to 15 pounds of loss and adjust your calorie target accordingly. Resistance training also helps by maintaining muscle mass, which supports your metabolic rate.
A Simple Starting Checklist
- Calculate your TDEE using the Mifflin-St Jeor equation or an online calculator
- Subtract 500 calories from that number to set your daily target
- Confirm your target stays above the floor: 1,200 for women, 1,500 for men
- Set a protein goal of 0.7 to 1.0 grams per pound of body weight
- Track your food for at least two to three weeks to calibrate your awareness
- Build meals around filling, whole foods: vegetables, lean protein, potatoes, legumes, eggs
- Weigh yourself daily and compare weekly averages rather than individual readings
- Recalculate every 10 to 15 pounds of weight loss to stay on track