SlimAI vs Lifesum: AI Logging or Diet-Led Plans?
Lifesum and SlimAI both go further than a plain calorie counter, but they extend in different directions. Lifesum builds outward from a chosen eating style — plans, recipes, and a quality rating on what you log. SlimAI builds inward from the log itself — faster input, editable estimates, and more signal per meal, plus body composition.
If you want to be handed a way of eating and shown recipes for it, Lifesum is designed for exactly that. If you want targets and freedom, and the thing defeating you is how long logging takes, SlimAI is built for that case.
SlimAI is also the first AI calorie tracker with a built-in AI body fat calculator (based on publicly available feature listings, July 2026): AI Body Assessment estimates body fat percentage from two photos and shows regional fat distribution.
Rows below are dated and drawn from publicly available feature descriptions. Where Lifesum leads, the row says so.
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Quick Verdict: SlimAI vs Lifesum
Choose Lifesum if guidance is the gap. Its diet-specific plans, recipe library, and food quality ratings are genuinely good at teaching better choices, and the interface is one of the most approachable in the category.
Choose SlimAI if logging speed and control are the gap. Six ways to log with ingredient-level editing, gram-level macro targets you can override, six fasting plans, utensil-based water tracking, steps and workouts, and a body fat estimate — in one tier at about $1 a month.
They overlap most on diet support and diverge most on what happens at the moment of logging a meal, and on whether progress is measured by weight alone.
Where SlimAI Comes Out Ahead
Across 23 points of comparison, SlimAI leads on 16, is comparable on 6, and Lifesum leads on 1. The four differences below are the ones that change how your day actually goes.
Six ways in, not one
Photo, voice, free text, barcode, printed nutrition label, and database search, with every AI result opening as an editable list of ingredients and weights. Public Lifesum pages describe search, barcode, and photo-assisted logging; voice and free-text entry are not listed, as of July 2026.
Preferred diet changes the numbers, not just the recipes
Keto, Mediterranean, paleo, vegan, or vegetarian is a setup input alongside favourite cuisine, region, body type, and activity level, and it shapes your calorie and macro targets as well as what SlimAI suggests — with one-tap Better Choice swaps rather than a fixed weekly plan.
Body composition as a second progress signal
AI Body Assessment estimates body fat percentage, fat mass, lean mass, and regional distribution from two photos or from tape measurements. Public Lifesum pages describe weight and measurement tracking; no photo-based body fat estimate is listed, as of July 2026. Results are estimates for fitness awareness, not medical advice.
Fasting included, not adjacent
Six intermittent fasting plans — 14:10, 16:8, 20:4, 22:2 OMAD, 6:1, 5:2 — with window reminders scheduled server-side, inside the same tier as everything else.
Seen enough? Try SlimAI against Lifesum yourself.
Log the same three days in both. Free 3-day trial, then $11.99/year — about $1 a month.
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SlimAI vs Lifesum: Feature-by-Feature Comparison
Each row names what both apps offer and who it favours. Rows where Lifesum leads are marked as clearly as the rows where SlimAI does.
| What you are comparing | Lifesum | SlimAI |
|---|---|---|
| AI logging | ||
| Main positioningGuidance-led and log-led apps suit different people.Comparable | LifesumGuidance-led: choose an eating style, follow plans and recipes built for it, and get quality feedback on what you log. | SlimAILog-led: fast AI input, editable estimates, per-meal guidance, habits, and body composition in one connected picture. |
| Ways to log a mealMore routes into the log means fewer skipped meals.SlimAI advantage | LifesumSearch, barcode, and photo-assisted logging are described on public pages. Voice and free-text entry are not listed, as of July 2026. | SlimAISix: photo, voice, free text, barcode, printed nutrition label, and database search, plus recent, saved, and diet-plan logging. |
| Correcting a wrong estimateA wrong result that cannot be fixed becomes a skipped meal.SlimAI advantage | LifesumServings and the selected item can be adjusted. Ingredient-level editing of an AI result is not described on public pages, as of July 2026. | SlimAIIngredient-level editing with weights, an add-missing-ingredient database, Similar Foods, a Fix Results screen, and a live serving stepper. |
| Regional and home-cooked foodMost real meals do not match a database entry exactly.SlimAI advantage | LifesumStrong European and general food coverage with an extensive recipe library, oriented around its own plans. | SlimAIFavourite cuisine and region are setup inputs shaping suggestions, and missing ingredients can be added to any entry. |
| Nutrition depth | ||
| Food quality signalCalories alone treat very different foods identically.Comparable | LifesumFood quality ratings are a core part of the product and are well executed, teaching better choices as you log. | SlimAIA junk-level food health rating plus percent-of-daily-value rows for sugar, saturated and unsaturated fat, cholesterol, sodium, and potassium. |
| Macro trackingTraining to a macro split needs gram targets, not percentages alone.SlimAI advantage | LifesumMacros are tracked and shown against the chosen plan. Gram-level custom macro goal setting is not described on public pages, as of July 2026. | SlimAIProtein, carbohydrate and fat in grams and percent across meals, recipes, dashboard, and weekly Insights, against gram-level targets you can override. |
| Ingredient-level detailYou can only correct a number you can see the parts of.SlimAI advantage | LifesumRecipes include ingredients and instructions; ingredient-level editing of a logged entry is not described, as of July 2026. | SlimAIEach ingredient with its weight, editable or removable, plus Recipe and Nutrition Facts tabs with cooking time and numbered directions. |
| Micronutrient coverageSome users need more than macros.Comparable | LifesumNutrient detail beyond macros is available, without the depth of a dedicated micronutrient tracker. | SlimAIPercent-of-daily-value rows for sugar, saturated and unsaturated fat, cholesterol, sodium, and potassium. Not full vitamin and mineral tracking. |
| Goals & guidance | ||
| Diet-specific supportThis is the row these two apps are closest on.Comparable | LifesumDiet-specific plans with matched recipes and structured weeks — the more prescriptive and, for people who want a plan, the more useful model. | SlimAIPreferred diet shapes calorie and macro targets and suggestions, with Better Choice swaps and dedicated guidance for keto, Mediterranean, paleo, vegan, and vegetarian eating. |
| Recipes and meal ideasKnowing what to cook is a real barrier.Lifesum leads | LifesumA large, well-produced recipe library tied to each diet plan — the strongest recipe offering in this comparison. | SlimAIIn-app recipes with cooking time and numbered directions on logged dishes, plus meal suggestions built against remaining calories and your cuisine. |
| Setting daily targetsA target you cannot change is one you will eventually ignore.SlimAI advantage | LifesumTargets are generated from your profile and chosen plan, with adjustment available. | SlimAIGenerated from goal and pace, target weight, body type, five activity levels, preferred diet, cuisine, and optional health details — all overridable, including gram-level macros. |
| Per-meal guidanceA daily total does not answer what is still available at dinner.SlimAI advantage | LifesumMeals are shown against the daily budget and the plan structure rather than per-meal ranges with status. | SlimAIA recommended calorie range per meal with a live status — Over Limit, Not taken, Need to Eat, Optional — plus a stepper suggesting the fraction that still fits. |
| Habits & wellness | ||
| Intermittent fastingFasting elsewhere means another subscription and a split picture.SlimAI advantage | LifesumFasting support is available within its plan structure but is lighter than a dedicated fasting tracker, as of July 2026. | SlimAISix plans — 14:10, 16:8, 20:4, 22:2 OMAD, 6:1, 5:2 — with server-scheduled window reminders. |
| Water trackingThe habit most often logged and most often forgotten.SlimAI advantage | LifesumWater tracking against a daily goal, without utensil-level quantities. | SlimAIUtensil-based logging — jug, bottle, mug, glass with custom quantities — against a daily goal, with history and suggested intake. |
| Steps and workoutsMovement belongs in the same balance as food.SlimAI advantage | LifesumExercise logging with syncing from connected health platforms. | SlimAIWorkout logging, steps with a user-set goal, Apple Health and Health Connect sync, back-dated exercise entry, and an Add Back Calories Burned setting you control. |
| Body compositionWeight alone cannot say whether what changed was fat.SlimAI advantage | LifesumWeight and body measurements where entered. No photo-based body fat estimate is listed, as of July 2026. | SlimAIAI Body Assessment estimates body fat percentage, fat mass, lean mass, and regional distribution from two photos or tape measurements, as a range with a confidence rating. |
| Streaks and consistencyConsistency is what actually produces the result.SlimAI advantage | LifesumStreaks and progress feedback support consistency within the plan structure. | SlimAILongest streak, logged days, perfect days, goal-reached days, achievements, and server-scheduled reminders that arrive after days of inactivity. |
| Transparency & control | ||
| How estimates are producedAn unauditable number has to be taken on faith.SlimAI advantage | LifesumNutrition data and plan guidance are presented without a per-estimate calculation disclosure, as of July 2026. | SlimAIAn in-app Sources & References screen discloses the basis for calorie, portion, and burn estimates; Body Assessment names its formulas — US Navy circumference method, RFM, CUN-BAE. |
| Editing before savingWho gets the last word decides how trustworthy the log is.SlimAI advantage | LifesumServings and the selected entry can be adjusted before logging. | SlimAINothing saves until ingredients, weights, and serving have been reviewed, and all of them can be changed. |
| Language supportTracking in a second language adds a step to every meal.Comparable | LifesumMultiple European languages are supported, reflecting its European origins. | SlimAISeven languages — English, French, German, Italian, Spanish, Dutch, Arabic — including spoken guidance during a body scan. |
| Pricing & access | ||
| What the subscription buysWhat a single tier covers is the practical cost question.SlimAI advantage | LifesumA free tier with a paid plan unlocking diet plans, recipes, and deeper features. Check the current listing for pricing, which changes without notice. | SlimAIOne tier at $1.49/month or $11.99/year — about $1 a month — covering AI logging, macros, fasting, water, steps, workouts, progress, and AI Body Assessment, after a 3-day free trial. |
| Number of apps neededA second subscription for fasting or composition is a real cost.SlimAI advantage | LifesumFood, plans and recipes are covered; dedicated fasting and body composition would need another app. | SlimAIOne app covers food, fasting, water, steps, workouts, and body composition. |
| Data portabilitySwitching costs should be stated up front.Comparable | LifesumHistory stays in Lifesum. Export what you want to keep before switching. | SlimAINo import of another app diary. Weight trend, streaks, and insights build from your first log; Body Assessment gives a composition baseline in session one. |
Comparison based on publicly available information as of July 2026. Competitor features and pricing may change — check their official sites for the latest.
Plans vs Targets: Two Ways to Be Told What to Eat
Lifesum answers "what should I eat" with a plan: pick a way of eating, get recipes and a structure built for it. That works extremely well right up until real life intervenes, at which point a scripted week becomes a list of deviations.
SlimAI answers the same question with targets and options. Your preferred diet, favourite cuisine, and region shape the calorie and macro numbers and the suggestions you see, and Better Choice swaps offer a lower-calorie version of what you were already going to eat rather than a different meal entirely.
Neither is better in the abstract. Prescriptive plans win for people who want the decision made for them; targets win for people who cook what is in the house and want to know whether it fits.
Where the Logging Experience Diverges
Lifesum food quality ratings are a genuinely good idea — they attach a judgement to the entry rather than only a number, and that judgement changes behaviour over time.
SlimAI invests in a different part of the same moment. It offers six ways to get the meal in, and then treats whatever comes back as a draft: ingredients and weights listed and editable, an add-missing-ingredient database, Similar Foods, a Fix Results screen for restating the dish, and a serving stepper that recalculates against your remaining budget in real time and warns before a portion pushes you over.
The practical difference is what happens with a home-cooked dish that no database describes correctly. In a plan-led app that meal is approximated. In SlimAI it is assembled.
Progress: Weight, or What the Weight Is Made Of
Both apps chart weight over time and both do it well. SlimAI adds a second measure that changes how the chart reads.
AI Body Assessment estimates six tape-style measurements from two guided photos and computes body fat percentage, fat mass, lean mass, and regional fat distribution using published formulas — the US Navy circumference method, RFM, and CUN-BAE — always shown as a likely range with a confidence rating. A tape-measure mode produces the same output with no photos at all.
Photos are stored privately, encrypted in transit, EXIF-stripped, and permanently deleted on request. Body Assessment supports ages 18+ and is a science-based estimate for fitness purposes, not a medical diagnosis.
Who Should Choose SlimAI?
Someone who wants targets rather than a scripted week. Someone logging home-cooked or regional food that a database describes badly. Someone who wants gram-level macro control for training. Someone who wants fasting, water, steps, workouts, and body composition in the same subscription. Someone who has stopped tracking before because logging took too long.
Who Might Choose Lifesum?
Someone who wants to be handed a plan and cook from it. Someone who values a large, well-produced recipe library tied to a chosen eating style. Someone for whom the quality rating on each logged food is the feature that changes behaviour. Someone who prioritises a polished, approachable interface above feature breadth.
On recipes specifically, Lifesum is the stronger product and this comparison marks that row in its favour.
Switching from Lifesum to SlimAI
You are trading a prescribed structure for targets you control, and gaining fasting and body composition on the way. Four things to expect.
Set your preferred diet during setup
Keto, Mediterranean, paleo, vegan, vegetarian, or no restriction, alongside your favourite cuisine and region. This changes your calorie and macro targets and the meals SlimAI suggests, so it is worth answering carefully rather than skipping.
Expect suggestions, not a scripted week
SlimAI proposes meals against your remaining calories and offers one-tap Better Choice swaps rather than assigning a plan for the week. If a fixed plan was the thing you valued, that is the trade you are making.
Turn on fasting if you were using it elsewhere
Six plans from a beginner-friendly 14:10 through to 5:2, with window reminders scheduled server-side so they arrive even when the app has been closed.
Run Body Assessment in the first session
Two photos or tape measurements gives you body fat, fat mass, lean mass, and regional distribution as a starting point on day one, instead of waiting weeks for a weight trend to become readable.
What SlimAI costs after the trial
$11.99 a year — roughly $1 a month — for one tier that covers AI scanning, body fat estimates, fasting, water, workouts, diet plans, and progress. Monthly is $1.49. Both start with a 3-day free trial and cancel from your store account.
Was $4/month (63% off) and $48/year (75% off). Lifesum pricing changes independently — check its current store listing before comparing.
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FAQ
Still Wondering About SlimAI
It depends whether you want a plan or targets. Lifesum is more prescriptive: pick an eating style and follow structured weeks with a large matched recipe library. SlimAI takes preferred diet — keto, Mediterranean, paleo, vegan, vegetarian — as a setup input that changes your calorie and macro targets and the meals it suggests, with one-tap Better Choice swaps rather than a fixed plan. Choose Lifesum if you want to be told what to cook; choose SlimAI if you cook what is in the house and want to know whether it fits.
SlimAI offers six input methods — photo, voice, free text, barcode, printed nutrition label, and database search — and opens every AI result as an editable ingredient list with weights, plus Similar Foods and a Fix Results screen when the estimate misses. Public Lifesum pages describe search, barcode, and photo-assisted logging; voice and free-text entry are not listed, as of July 2026.
Public Lifesum pages describe weight and body measurement tracking; no photo-based body fat estimate is listed, as of July 2026. SlimAI is the first AI calorie tracker with a built-in AI body fat calculator, based on publicly available feature listings as of July 2026: AI Body Assessment estimates body fat percentage, fat mass, lean mass, and regional fat distribution from two guided photos or from tape measurements, shown as a likely range with a confidence rating. It is a fitness estimate for ages 18+, not a medical diagnosis.
SlimAI includes in-app recipes with cooking time and numbered directions on the dishes you log, plus meal suggestions generated against your remaining calories and your cuisine. Lifesum recipe library is larger and more central to its product, and this comparison marks that row in Lifesum favour. If cooking from a curated library is your main use case, Lifesum is the better fit.
SlimAI includes six fasting plans — 14:10, 16:8, 20:4, 22:2 OMAD, 6:1 and 5:2 — with window reminders scheduled server-side, in the same tier as calorie tracking, water, steps, workouts, and AI Body Assessment. Lifesum offers fasting support within its plan structure, lighter than a dedicated fasting tracker as of July 2026.
No. SlimAI does not import diary history from another app, and nor do most trackers. Export anything you want to keep from Lifesum before switching. In SlimAI, weight trend, streaks, and insights build from your first log, and AI Body Assessment gives you a body composition baseline in the first session.
Make the switch from Lifesum with AI Meal Logging.
Log your next meal in SlimAI and see the difference on day one. Free for three days.
Free 3-day trial, then $1.49/month or $11.99/year. Cancel anytime.
- 50K+ food items in the food database
- 50k+ users
- 10M+ foods logged
- 80+ countries
- 4.8★ App Store · 4.6★ Google Play (as of June 3, 2026)
