How much should you eat for fat loss after 40?
Your maintenance calories, fat loss target, and macro split in 30 seconds.
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Cardio and lifting combined. If you don't exercise right now, put 0.
Used for your protein target. If you're not sure, use your current weight.
Optional. Only if you have a DEXA or InBody scan from the last few months. Skip it otherwise, because an estimated body fat number makes the result less accurate.
Your numbers
A BMR under 1,200 is common for smaller women. It comes from your height and weight and says nothing about how well your metabolism works. It does mean your maintenance is on the lower side, so keep the deficit small. Muscle is the one tissue that raises BMR over time, so lifting matters even more for you.
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This calculator is for education only and isn't medical advice. I'm a certified nutrition coach, not a doctor or registered dietitian. Talk to your doctor before changing how you eat, especially if you have a health condition or take medication.
What do these numbers mean?
BMR (basal metabolic rate) is the number of calories your body uses in a full day of complete rest. It covers breathing, circulation, body temperature, and cell repair. For a woman who is not very active, BMR is around 60 to 70% of her total daily calories. Your maintenance and your Fat Loss Target are both calculated from it.
TDEE (total daily energy expenditure) is your BMR plus the calories you use moving through your day and working out. This is your maintenance. Eat this amount and your weight holds steady.
Fat Loss Target is your maintenance minus a deficit of 10 to 20%. A deficit in that range is small enough to protect your muscle and large enough to lose about 0.5 to 1 lb a week. In one study, researchers split athletes into 2 groups. The slower group lost about 0.7% of body weight a week and the faster group lost about 1.4%. Both groups lost the same amount of fat, but only the slower group gained muscle and strength along the way.
Sources: Garthe et al., 2011, International Journal of Sport Nutrition and Exercise Metabolism; Helms et al., 2014, review.
How accurate is this?
Your BMR is calculated with the Mifflin-St Jeor equation, the standard in clinical dietetics. The Academy of Nutrition and Dietetics compared the common equations against metabolism measured in a lab. Mifflin-St Jeor came closest, landing within 10% of the measured number for 7 to 8 out of every 10 adults. If you entered a body fat percentage from a scan, we used the Katch-McArdle equation instead. It calculates from your fat-free weight directly, which is more precise when that number is accurate.
Your activity is added in 2 parts. Your normal day sets a standard activity factor of 1.2 to 1.725, the same range dietitians use. Your workouts are added separately, using MET values from the Compendium of Physical Activities. That is a published database of the energy cost of hundreds of activities, so your training counts the way you described it.
Every equation is an estimate. The lab comparison above means roughly 2 in 10 women will be more than 10% off. On a 1,700-calorie maintenance, that is about 170 calories a day. That is why Step 4 exists. After 2 weeks of eating your target, your own weight change shows whether the estimate ran high or low, and we correct it from there.
Sources: Frankenfield et al., 2005, Journal of the American Dietetic Association; Compendium of Physical Activities.
Your macros
Your calorie target decides how much weight you lose. Your macros, meaning the protein, carbs, and fat those calories come from, decide how much of that weight is fat and how much is muscle. With enough protein and regular lifting, far more of what you lose is fat. Without them, a meaningful share of what comes off is muscle. Muscle is the tissue that gives your body its shape and keeps your metabolism up.
0.7 g per lb of goal weight is the floor for protecting muscle while you lose fat. Protein also keeps you full for longer than carbs or fat do, which makes the deficit easier to stick to.
Carbs fuel your workouts and fat supports your hormones. Both splits work for fat loss as long as total calories stay the same, so pick the one you can live with.
Your carbs land under 130 g, the daily minimum set for your brain. Pick the balanced plan instead.
Build a strong, toned core while you lose weight
The Strong Core Method is 3 workouts a week at home, about 20 minutes each.
See the Strong Core MethodWhere the protein numbers come from
In a deficit, protein is what protects your muscle. Researchers pooled 49 studies of adults who were lifting weights. Muscle gains kept rising with protein intake up to about 1.6 g per kg of body weight a day, then leveled off. That works out to 0.73 g per lb, which is where our Minimum sits. The upper end of that range was about 2.2 g per kg, or 1 g per lb.
When calories are reduced, your body is more likely to break down muscle for fuel, so the case for the higher end gets stronger. That is why 1 g per lb is the better target. A review of athletes dieting for competition recommended higher still, 2.3 to 3.1 g per kg of fat-free weight. That is where our 1.2 g per lb option for women lifting 4 to 5 days a week comes from.
We calculate from your goal weight rather than your current weight. That way the number reflects the body you are building, and it stays reasonable for a woman with a lot of weight to lose.
Sources: Morton et al., 2018, British Journal of Sports Medicine; Helms et al., 2014, Journal of the International Society of Sports Nutrition.
Why fat never goes under 25%
Your body uses dietary fat to make hormones, including estrogen, and to absorb vitamins A, D, E, and K. The Institute of Medicine sets the acceptable range for fat at 20 to 35% of total calories. We stop at 25% rather than 20% to leave a margin. When your total calories are already reduced, the low end of that range gets small fast. On a 1,500-calorie target, 20% fat is 33 g a day, which is about 2 tablespoons of olive oil.
The same guidelines set 130 g a day as the minimum carbohydrate intake, based on what your brain uses for fuel. That is why the calculator warns you if a split would take you under it.
Fat has 9 calories per gram, and protein and carbs have 4, so the higher-fat split means smaller portions for the same calories.
Source: Institute of Medicine, Dietary Reference Intakes for Energy and Macronutrients.
Fine-tune your numbers
The maintenance number and Fat Loss Target you got in Step 2 are estimates. A formula can't account for your muscle, hormones, genetics, or how much you really move. The only way to confirm your target is right is to eat it for 2 weeks and compare what happened with what the formula predicted.
Eat your Fat Loss Target for 14 days. Weigh yourself on day 1 and day 15, at the same time of morning and before you eat. Then come back to this step and answer 2 questions. We compare your result with the loss the formula expected. If they disagree, we adjust your maintenance and your target in small steps, never more than 150 calories at a time.
Your weight can fluctuate from day to day because of water, salt, sleep, and your cycle. Weighing 2 weeks apart smooths most of that out. If day 15 lands on a day you'd normally be puffy, wait a day or 2.
Build a strong, toned core while you lose weight
The Strong Core Method is 3 workouts a week at home, about 20 minutes each.
See the Strong Core MethodFor informational purposes only. Not medical advice. Consult your healthcare provider before changing your diet or exercise.