If you’re like many women in midlife trying to get a handle on your health, maybe you’ve found yourself wondering:
“How many calories should I actually be eating to lose fat?”
“What should my macros look like for my age and body?”
And the big one…
“Can someone just tell me what to eat?!”
I get it. There is so much info out there that it can feel overwhelming. And that’s exactly why I’m so excited to show you how I use AI tools like ChatGPT to help my clients (and myself!) calculate calories and macros for sustainable fat loss, and even create realistic meal plans — all in just a few clicks.
This isn’t about gimmicks or generic advice. It’s about using smart tools to get a starting point tailored to you, your lifestyle, your body, and your goals — so you can stop guessing and start getting results.
Click the play button to watch as a video, or carry on reading below.
Why Use AI for Your Nutrition?
Before we dive in, let me just say: no tool will ever replace learning to listen to your body or building sustainable habits over time. But tools like ChatGPT are amazing for giving you a personalised baseline, a place to start working from — and saving hours of Googling, overthinking, and second-guessing.
This is the same process I use with my Better Body and 1:1 clients, and it’s super helpful especially when you’re just starting out or looking to reset your nutrition.
Let’s walk through the exact steps…
Step 1: Get Your Calorie & Macro Targets
I start by asking ChatGPT to calculate estimated calories and macronutrients based on key client info like
- Age
- Gender
- Height
- Weight
- Activity level
- Goal (fat loss, muscle gain, etc.)
You can use this following prompt:
Help me calculate my BMR (Basal Metabolic Rate) and daily calorie needs step by step by asking me one question at a time.
Please also estimate my lean body mass, and use that to calculate my macros using 1 gram of protein per pound of lean body mass. Then, calculate my daily fat and carbohydrate targets based on a maximum 25% calorie deficit from my TDEE (Total Daily Energy Expenditure). I want a clear, easy-to-understand breakdown that includes:
- My BMR
- My TDEE
- My estimated lean body mass
- My protein, fat, and carb targets in grams
- My total daily calories for fat loss
Please ask me the questions you need to get started, and guide me through the whole calculation process like a coach would
For example, one of my female clients is 59, 5,4″, 72kg, with a sedentary desk job but also trains 3x per week (2 strength, 1 pilates). Her main goal is body recomposition — building lean muscle and losing fat slowly and steadily.
Using ChatGPT, I can plug in all of that and get a clear starting point with her estimated calorie needs, plus a full macro breakdown (protein, carbs, fat).
💡 Tip: If your goal is fat loss, we’ll usually start with a small calorie deficit — around 10-25% calories under maintenance — while keeping protein high to support muscle retention.
Step 2: Use ChatGPT to Get Your Macros
Here’s the prompt I used to get ChatGPT to generate my calorie and macro targets, plus a sample meal plan:
PROMPT:
Create a 1-day meal plan for a peri-menopausal 43-year-old female who trains 4–5x/week, aiming for fat loss and improved body composition. She prefers a high-protein, lower-carb approach with roughly 1600 calories per day, under 100g carbs, 30g fibre, and at least 140g of protein.
You can copy and paste that prompt into ChatGPT (or tweak it based on your goals). The key is being specific about:
- Your age and life stage
- Training frequency
- Food preferences
- Macros and calories
Step 3: Adjust & Personalise
What I love about using AI like ChatGPT is that you can adjust the plan easily:
- Want more variety? Ask for a 3-day plan.
- Prefer dairy-free or gluten-free? Add that to the prompt.
- Don’t like eggs? Just say so.
It’s not a rigid meal plan — it’s a launch pad to help you understand what your plate should look like to hit your goals without tracking obsessively or second-guessing every meal.
Step 4: Use It as a Baseline, Not a Bible
I always tell my clients: This isn’t about perfection. It’s about having a roadmap.
Use these targets as a guide — then practice tuning into your own hunger, energy, and progress as you go.
As you start to eat more protein, balance your plate, and fuel your body consistently, you’ll naturally build the habits that make results sustainable long-term.
Bonus: Make Adjustments Over Time
What I love most about using AI in this way is that it gives you a foundation to build on.
As you track progress (maybe with body measurements, progress pics, energy levels, strength, or how your clothes fit), you can adjust things slowly based on what’s working.
Maybe you add in more carbs on training days, or slightly lower calories on rest days.
Maybe you tweak the protein goal depending on how full you’re feeling.
Maybe you just get more creative in the kitchen with your meals!
And the beauty is, ChatGPT can help you adjust as you go.
Want Help With This?
If you’re over 40 and trying to lose fat, build strength, or just feel better in your body, I’ve got loads of free content to help you with this — and I also offer 1:1 coaching and structured programs where I walk you through this whole process step by step.
And if you want to try this yourself, just open ChatGPT and say:
“Act as a nutritionist. I’m a [your age] year old [female/male], [your weight], [your height], [activity level]. My goal is [fat loss/body recomposition/muscle gain]. Can you calculate my estimated calories and macros, and create a sample day of eating?”
It’s that easy. ✨
Let me know if you try it — I’d love to hear how it works for you!
Want me to help you with your numbers and plan? Shoot me a message on Instagram @emmacolseynicholls or email me at info@emmacolseynicholls.com — I’d love to support you. Or check out Better Body coaching and I can walk you through this and also support you in actually putting it into action
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