Over the past four months, I've increasingly spent time putting a system in place to monitor my nutritional intake - and by extension my health. Simplistically, my goal has been to gain strength while losing fat - with a focus on improving overall health.
I've worked out a nice system using three tools: Cronometer, Apple Watch, and Fitbit Aria.
Cronometer is used as a food diary to log consumption. Beyond tracking caloric intake, it also helpfully breaks out food into both macro- and micronutrients. For example, you can see your protein intake, but also see the percentage of Isoleucin, Leucine, and Valine consumed (important for muscle gain).
Since my focus is on strength gains, I have macronutrient targets set to Protein @ 35%, Carbohydrates @ 45%, and Fat @ 20%. That's working well for me, but you should choose for your own goals and body.
Since my secondary focus is on losing fat, I have Cronometer set to lose 1 pound per week as my Weight Goal.
Another critical component of this setup is my Apple Watch - which logs Active Caloric burn. I use it throughout the day, and log every workout using it. Then, at least once a day - at the end of the day - I open Cronometer on my iPhone which syncs with HealthKit.
Cronometer takes the Active Caloric burn from Health and adds that to the Base Metabolic Rate calculated based on my current weight. Active + BMR = Total Caloric Burn.
Lastly, I use the Fitbit Area smart scale which uploads my weight and (rough) body fat % to the cloud which syncs with Cronometer. As a consequence, Cronometer updates my BMR daily (and thus caloric intake goal).
In summary, I use a food log for daily food intake and to calculate a target daily caloric intake. I use a smart scale to automatically update my weight which correspondingly updates my caloric intake target. And I use a fitness watch to capture additional calories burned throughout the day which are additive (burn more, eat more).
It's working great for me. Now, the real trick: can I turn 4 months into 4 years of sustained progress.