Diet Tracker 
How it works
Log what you eat
Build your own food list, then log a meal in a tap or two: starred foods appear as one-tap buttons, and anything else is a quick search. Change the portion later if you ate less than planned. New foods can be looked up in the USDA FoodData Central database or by barcode in Open Food Facts, so you rarely type numbers by hand. Net carbs are total carbohydrate minus fiber and sugar alcohols.
Daily targets that change over time
Net carbs are the limit in every plan, with a protein minimum and a calorie maximum. Targets are dated: when you change them, earlier days keep the targets they had, and History marks the change.
Keto or South Beach
Choose a plan in Settings. Keto keeps one steady, low net-carb limit. South Beach runs in three phases: a strict 14-day Phase 1, then Phase 2 adds carbs back in 10g steps while you keep losing (up to about 100g), then Phase 3 holds your weight. Today shows where you are, such as “day 9 of 14”.
The app watches your trend weight (a 7-day average, and the rate fitted over two weeks, so one salty dinner doesn’t count as a setback) and suggests a change when it’s time:
- Phase 1 is done: move to Phase 2.
- Phase 2 and on pace for your target loss: add 10g of carbs. Loss has stalled: drop back 10g.
- Goal reached: move to maintenance. Weight back up more than 3 lb: return to Phase 1.
- Keto and loss has stalled: trim 100 calories.
Suggestions never change anything on their own; you apply or dismiss them.
Goals without BMI
Set a weight goal, a body-fat goal and a target pace in pounds per week. With your sex and age, the app shows a healthy body-fat range for you. From your latest body-fat reading it works out your lean mass and the weight at which you’d reach your body-fat goal. With your height it reports fat-free mass index (to see that you keep muscle while losing fat) and, if you log your waist, waist-to-height ratio.
History
Weight, body fat and waist charts with your goals, daily or weekly columns for each macro against the targets in force each day, which plan you were on when, and a day-by-day table.
Your data stays yours
Each account is private, and you can skip the account entirely: Use Locally Only keeps the whole diary in your browser and works offline. Either way, export your foods and history as JSON at any time (file format), import them elsewhere, or delete your account and everything in it from Settings. When you add a USDA food, only USDA’s official record is shared with other users, never your diary or your edits.
Sources and guidance
Diet Tracker is a logging tool, not medical advice. The defaults below come from published guidance; your doctor’s numbers should take precedence, and every target can be changed.
- South Beach phases and net-carb levels: Mayo Clinic, South Beach Diet. Its keto-friendly version starts at 20–50g of carbs a day and rises over time to 75–100g; the app defaults to 50g in Phase 1. See also Healthline’s overview.
- Healthy body-fat ranges by age and sex: Gallagher D, et al. Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index. Am J Clin Nutr 2000;72:694–701. The authors describe the ranges as provisional.
- Waist-to-height ratio under 0.5: NICE (UK National Institute for Health and Care Excellence), Overweight and obesity management (NG246): “keep their waist to less than half their height”. Measure midway between the lowest rib and the top of the hip bone, just above the belly button, after breathing out.
- Fat-free mass index: Kouri EM, et al. Fat-free mass index in users and nonusers of anabolic-androgenic steroids. Clin J Sport Med 1995;5:223–228.
- Food data: USDA FoodData Central and Open Food Facts (ODbL).