App Comparison

Carb Manager vs Lifesum

Fuel Nutrition Team • March 16, 2026

Carb Manager and Lifesum serve different tracking philosophies. Carb Manager is purpose-built for keto and low-carb eating with specialized tools for that framework. Lifesum recently pivoted to AI-powered logging with broader diet plan support. Both offer more than basic calorie counting — but with different trade-offs.

Dietary Framework

Carb Manager is keto-specific: net carb tracking that subtracts fiber and sugar alcohols, ketosis targets, keto recipes, and meal plans tuned to low-carb macros. If you're doing keto, the tooling is purpose-built.

Lifesum takes a broader approach with multiple diet plan options — keto included — but none as deeply integrated as Carb Manager's keto tools. Lifesum's strength was lifestyle scoring and approachable design, though the AI pivot has shifted the experience.

Food Logging

Carb Manager uses traditional database search with free barcode scanning. The keto-specific entries include proper net carb calculations. It's slower than AI logging but produces reliable numbers for its target diet.

Lifesum's AI text logging is faster in theory but accuracy is questioned. The ability to correct entries was removed in the AI update, and meal structure was replaced with a flat list that mis-assigns foods to wrong meal slots.

Meal Planning & Recipes

Both offer meal planning, but Carb Manager's is more developed — a full weekly meal plan builder tuned to keto macros. The builder crashes and preference filters don't always work, but the concept is a genuine differentiator.

Lifesum offers diet plans and recipes behind its subscription, but they're less specialized and less integrated into the daily tracking workflow.

Verdict

If you're following keto or low-carb, Carb Manager at $7.99/month is the better fit — purpose-built tools, free barcode scanning, and a keto-specific ecosystem. If you want AI-powered logging with broader diet flexibility, Lifesum offers more dietary approaches — but the AI pivot has introduced reliability issues that affect the daily experience.

Want nutrition tracking that adapts to any diet — keto, general, or anything else — with AI logging that works? Fuel combines correctable AI logging with adaptive coaching, at a fraction of either app's premium price.