Turn ChatGPT Into a Personal Expert in 60 Seconds
There's a version of ChatGPT — or any AI — that gives you the same answer it gives everyone else.
Vague. Generic. Kinda helpful. The kind of advice you'd get from a very well-read stranger at a bus stop.
And then there's the version you unlock when you give it a job title and hand it your actual situation. That version feels like a completely different tool. I know, because I built one — and it changed how I approach my health.
The 10kg I Lost by Asking Better Questions
About two months ago, I decided to get serious about my weight. I'd tried before, multiple times, and I know what it's like to start strong and quietly give up. This time I went in differently — I started doing real research. Reading about insulin, heart health, how different foods affect the body long-term. And I made genuine sacrifices around what I eat.
But research alone leaves gaps. I had specific daily questions that no article quite answered. And as an introvert, the idea of sitting across from a nutritionist and talking through my eating habits wasn't exactly appealing — not to mention the cost.
So I built Dr. Heart — a custom AI persona focused on heart health and overall wellness. Not to do the work for me, but to be the knowledgeable guide I could ask anything, any time. Is this meal going to work against me today? What's actually happening in my body when I eat this? What should I have before a workout on three hours of sleep?
The work was mine. The sacrifices were mine. But having a tool that could answer my specific questions — quickly, without judgment — helped me stay informed and consistent in a way I hadn't managed before. I've lost almost 10 kilograms in two months.
Now — before I go further — Dr. Heart is not my actual doctor. It has never seen my bloodwork. It does not replace a GP. Please still see a real medical professional for anything serious. AI can hallucinate. It can be confidently wrong. I cannot stress this enough.
But as a daily thinking partner, helping me make smarter decisions based on research I'd already done? It's been remarkable.
And here's the thing: the magic wasn't the AI. The magic was how I set it up.
The Difference Between "Ask AI" and "Ask Your Expert"
Most people open ChatGPT and type a question cold. That's like calling a consultant and saying "help me" — without telling them what you do, what you're dealing with, or what you've already tried.
When you give the AI a role and your personal context upfront, everything changes. The answers get sharper. More relevant. More yours.
I've now built a small team of these:
Dr. Heart — My go-to for anything related to heart health, overall wellness, and daily food decisions.
Mr. Chef — An expert in cooking techniques, ingredient swaps, and building meals around what I actually have in the fridge.
Mr. Clean — This one might surprise you. I got tired of not knowing whether cleaning products were safe to mix, or why certain methods actually work. Mr. Clean explains the chemistry in plain English. I've learned more about my home in three months than in years of just winging it.
None of these required a paid subscription or a tutorial. They're just AI — with a job description and my situation baked in from the start.
Two Ways to Build Your Expert (Both Free)
Path 1 — Gemini: Set it once, use it forever
This is what I use. Gemini has a free feature called Gems — you write your expert's persona once, save it, and it's there waiting every time you open it. Dr. Heart lives here. No copy-pasting, no setup each time. Just open and ask.
Go to gemini.google.com → click Gem Manager on the left sidebar → New Gem
Path 2 — ChatGPT: Paste and go
If you're already comfortable in ChatGPT, no need to switch. The free plan doesn't save personas between chats — so you'll paste your expert prompt at the start of each new conversation.
Pro tip: Keep your prompts in your Notes app or a Google Doc. One tap to copy, one paste to start. It takes about ten seconds and quickly becomes second nature.
The Prompt Template (Copy and Paste This)
Here's the exact structure I use. Swap in your own details:
You are [role] — a world-class expert in [specific area]. Your job is to give me practical, clear, and honest advice based on my specific situation. Here's what you need to know about me: [2–3 sentences about your relevant background, goals, or constraints]. When you answer, always explain the why in plain language. If something is outside your expertise or I should see a real professional, say so directly.
A real example, close to how I set up Dr. Heart:
You are a world-class wellness advisor specialising in heart health and nutrition. Your job is to give me practical, clear, and honest advice based on my specific situation. Here's what you need to know about me: I'm a busy professional in my 30s, currently on a weight loss journey, with a desk job and limited time to cook. I've been reading about how food affects heart health long-term, and I want to make smarter daily decisions. When you answer, always explain the why in plain language. If something is outside your expertise or I should see a real doctor, say so directly.
Paste that into a new chat. Then start asking your actual questions. You'll feel the difference immediately.
A Few Honest Caveats (Because I'd Rather You Trust Me)
AI can be confidently wrong. These tools don't know things the way a licensed professional does — they pattern-match across enormous amounts of text. Dr. Heart has occasionally given me suggestions I quietly set aside because they didn't feel right. Your gut and your doctor still matter.
Don't share information you wouldn't want stored online. Describe your situation in general terms — age range, lifestyle, goals. You don't need to hand over your full medical history to get genuinely useful answers.
The more specific your context, the better the output. A vague prompt gets vague answers. The 60 seconds you spend setting up your expert persona will pay you back every single time you use it.
Your Turn
Pick one area of your life where you'd love a knowledgeable friend on speed dial. Not a therapist, not a surgeon — something practical. A fitness coach. A meal planner. A home repair guide.
Open ChatGPT or Gemini. Paste the template. Fill in your situation.
Then ask it something you've been wondering about for months but never quite got around to looking up.
That's how it starts.
