The skill behind this guide: Freya - Nutrition & Diet Coach AI Skill. Weekly meal plans, shopping lists and habit changes built around the food you actually eat - $14.99, paid once, yours permanently.
View the Freya skill →Claude is good at the planning half of nutrition: a week of dinners that fit your budget, your kitchen and the twenty minutes you actually have on a Tuesday, plus the shopping list to match. It is bad at the arithmetic half. Every calorie and macro figure it prints is a guessed portion weight multiplied by a nutrient value recalled from training data, presented with the confidence of a measurement. Use it for the plan. Get the numbers from USDA FoodData Central.
What is Claude actually good at here?
Three things, all structural rather than numeric.
- Planning around constraints you list. Give it a headcount, a weekly budget, a cooking-time ceiling and the foods nobody in the house will touch, and it produces a week that respects all four and reuses ingredients so half a bunch of coriander doesn't rot in the drawer.
- Reworking the plan when a constraint changes. "Cheaper this week", "no oven, the element went", "my sister is vegetarian now" - it rebuilds the whole week and the shopping list, rather than patching one meal and leaving the list stale.
- Turning a vague intention into a specific behaviour. "Eat more vegetables" becomes "add frozen peas to the pasta you already make on Wednesdays". That translation step is the one most people skip, and it is the one that decides whether anything changes.
Why are its calorie and macro numbers guesses?
Two errors stack. First, portion weight: FoodData Central lists nutrients per 100 grams, and Claude has no scale. It reads "one medium chicken breast" or "a handful of almonds" and assigns a gram figure by assumption. Second, nutrient density: it recalls a value rather than looking one up, and recall drifts.
Then it multiplies the two and prints something like "612 kcal, 38 g protein" - three significant figures built on two estimates. Ask the same question in two separate chats and you will often get two different totals for the same plate of food. Nothing in the output tells you which parts were measured and which were invented, because none of it was measured.
Three more things it does not know:
- Current recalls. Training data has a cutoff. A product withdrawn last month is invisible to it.
- What is printed on the packet in your kitchen. Manufacturers reformulate, and allergen and "may contain" statements change with them. Claude cannot see your label. It should never be the thing that clears a food as safe for an allergy.
- Anything about you it was not told. No bloods, no medication list, no weight history. It cannot flag a food-drug interaction it does not know exists - the vitamin K and warfarin problem being the textbook case.
Get a professional to review the plan first if any of these apply to you
A diagnosed food allergy. A therapeutic diet prescribed by a clinician. Type 1 or type 2 diabetes. Kidney disease. Coeliac disease. A current or past eating disorder. Pregnancy or breastfeeding.
In every one of those cases the details Claude is worst at - exact portions, hidden allergens, potassium and protein loads, carbohydrate counts for insulin dosing - are the details that matter clinically. A registered dietitian or your doctor should see the plan before you eat off it. This guide, and the skill it describes, are general wellbeing tools, not medical or dietetic advice.
Freya asks about your tastes, budget and schedule before proposing anything, then plans around what you will still be doing in week three. Paid once, no subscription.
View Freya - Nutrition & Diet Coach AI Skill →How do you install the skill?
The download is a ZIP with a SKILL.md file at its root. In the Claude desktop app open Customize → Skills, upload the ZIP, and toggle the skill on. That is the entire install.
Skills run on Free, Pro, Max, Team and Enterprise - there is no paid-plan gate. The real requirement is code execution. On Free, Pro and Max, switch on Code execution and file creation under Settings → Capabilities. On Team and Enterprise an owner can disable that org-wide, which is why the menu sometimes looks greyed out: an admin setting, not your subscription.
On ChatGPT or Gemini, or stuck behind an admin who will not enable code execution? Open the ZIP, copy the text of SKILL.md, and paste it into custom instructions. You lose file handling; the persona and the rules still work.
Which prompts actually produce something usable?
Copy these as they are and fill in the brackets. The last block of rules in each is the part that stops the specific failure mode - do not delete it.
1. A week of dinners that survives contact with a real week
2. One habit change, ranked by how little it disrupts your day
3. Adapting a recipe to a dietary constraint without pretending to read labels
If what you need is the plan and the list rather than an ongoing coach, Paolo builds a 5-7 day plan plus a prep schedule for your household in one pass.
View Paolo - Meal Planner & Prep AI Skill →Where does it fail?
This is the section worth reading twice, because every failure below produces output that looks correct.
- It folds when you push back. Disagree with a suggestion and it will usually drop it rather than defend it. If you want an honest read - "tell me where this week is thin on protein sources" - you have to ask for the disagreement explicitly, and even then treat it as a prompt to check, not a verdict.
- It invents precision on request. Ask for gram weights and it will supply them. They are still guesses; they just look official now. A $12 kitchen scale beats every number it will ever give you.
- Open questions pull it toward the median internet answer. Ask "how do I lose weight" and you get whatever was most repeated in its training data, not something built from what you told it. Narrow, constrained questions get personal answers; broad ones get received wisdom.
- Micronutrients are the worst case. It will tell you a week "covers your iron and B12" without having counted anything, because that sentence pattern is common in its training data. Treat any micronutrient claim as unsupported.
- It cannot see the food. Freshness, storage, whether the chicken in your fridge is still fine - none of that is visible to it, and it will answer anyway.
- It forgets between chats. A loaded skill carries your constraints; a bare chat does not. Restating "no shellfish, no oven" every single time is not optional.
One plan for a household with mixed dietary requirements, in a single chat. No skill file, no install - paste and go.
View AI Meal Generator →Who is this for?
People who know roughly what they should be eating and keep failing at the logistics: the Tuesday-night decision, the shopping list, the fact that the plan assumed an oven. It is not a substitute for a dietitian and it is not a diagnostic tool. For the rest of the everyday, the health & medical skills collection covers wellbeing and self-care planning, and the grocery and pantry manager guide picks up where the shopping list starts.
In summary:
Want an ongoing coach that keeps your tastes and constraints between sessions? Freya, $14.99. Just want the weekly plan and shopping list? Paolo, $14.99. One quick plan for mixed dietary needs? The AI Meal Generator prompt pack, $9. All work in Claude, ChatGPT and any AI chat, no coding, 30-day money-back guarantee. None of them can count calories - that is what FoodData Central is for.
Freya - Nutrition & Diet Coach AI Skill
Upload one ZIP and it plans balanced meals, builds the shopping list, and proposes habit changes that fit your week. No subscription. Yours permanently.
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