If you ask how to lose weight, you’ll hear one answer on repeat: calorie deficit.
And yes, fat loss does require a deficit.
But here’s what no one explains properly: you cannot calculate a deficit until you know your maintenance calories, and for many women, especially in perimenopause, that’s where things go wrong.
A lot of women have been under-eating for years. They’re tired, inflamed, training hard, sleeping badly, and stuck.
Telling them to eat even less doesn’t create fat loss and does the opposite… It creates stress.
So let’s break this down properly.
Step 1: Calculate your maintenance calories (starting point)
This is the number you base weight loss on.
Option A: Use a formula (estimate)
BMR = (10 × weight in kg)
- (6.25 × height in cm) – (5 × age) – 161
Then multiply by activity level:
Sedentary: × 1.2
Lightly active: × 1.35
Moderately active (training 3–5x/week): × 1.55
Very active: × 1.7
BMR × activity factor = estimated maintenance calories
Example: 75 kg, 165 cm, 45 years
BMR ≈ 1,395
Moderately active → ~2,160 calories
This is a guide
Step 2: Confirm maintenance in real life
Track your food for 7–14 days.
Eat consistently, no extreme low days.
Weigh daily and look at the weekly average.
If your weight stays the same, the calories you’re eating = your true maintenance.
This step matters because hormones, stress, sleep, and past dieting change how your body responds.
Step 3: Decide if you need maintenance first
If you’ve been eating very low calories for months or years, going straight into a deficit usually backfires.
Signs you should sit at maintenance first:
• Constant fatigue
• Poor sleep
• High anxiety
• Training feels heavy
• Irregular cycles
Most women need 4–8 weeks at maintenance before fat loss works again.
Step 4: Calculate your calories for weight loss
Once maintenance is steady, this is the formula:
Weight loss calories = maintenance × 0.85–0.9
That’s a 10–15% deficit.
Example:
Maintenance = 2,100
Weight loss calories = 1,785–1,890.
This protects muscle, hormones, and training performance because it is not aggressive.
Step 5: Make the deficit work
Calories matter, but so does structure.
- Protein stays high.
Strength training stays in.
Steps stay consistent.
Sleep becomes non-negotiable.
Fat loss is not about eating less forever. It’s about eating the right amount for your body in this season of life.
Why this works when nothing else has
If calorie deficit hasn’t worked for you, it usually means:
• You didn’t know your real maintenance
• You were already under-eating
• Your body was stuck in survival mode
Weight loss starts working when your body feels safe enough to let go.
If you want help calculating your maintenance calories properly with food, hormones, and real-life stress factored in, please reach out.
There is a smart way to lose weight.
And it starts with the right numbers.
Book free 30 min Zoom consultation here: Discovery Call | Perimenopause Health
Reference:
Bytomski J. R. (2018). Fueling for Performance. Sports health, 10(1), 47–53. https://doi.org/10.1177/1941738117743913
