Intermittent fasting in Azetta: protocols, progressive plan and eating window

The principle

Intermittent fasting means eating within a limited time window and eating nothing outside it. Its effects come mainly from the fact that it helps some people eat less; it doesn't suit everyone, and it can get in the way of training if it is badly placed. Azetta therefore deals with three questions in order: are you allowed to fast, how far, and what time to eat so that your sessions stay fuelled.

The Azetta method

The protocols

20:4 and one meal a day exist in the code but are never offered: the app's ceiling is 18:6.

The blocking questions

No plan is offered if you are under 18, if you are pregnant or breastfeeding, if you take a treatment that must be taken with food (diabetes in particular), if you have or have had an eating disorder, or if your BMI is below 18.5.

The maximum protocol

The ceiling depends on your goal, then tightens according to your profile:

• weight loss or body sculpting: 18:6; all other goals: 16:8;
• 50 and over: at most 16:8; 65 and over: at most 14:10;
• BMI between 18.5 and 20: at most 14:10;
• muscle gain, or 5 or more sessions per week (sport included): at most 16:8.

5:2 is offered as soon as the ceiling reaches 16:8. You can always choose a gentler protocol.

The progressive plan

The plan climbs in 2-week stages from 12:12, then holds the target protocol for 4 weeks; after that it keeps it. To aim for 5:2: 2 weeks of 14:10, then 6 weeks of 5:2. The plan moves forward with the weeks, never on its own based on your check-ins.

The eating window

With no known training, the window is centred on 13:00, without starting before 08:00:

With your training times (morning 07:30, midday 12:30, evening 18:30), the window must open 90 minutes before the first session and stay open 60 minutes after the last; the start is then bounded between 07:00 and 13:00. The app checks each day of your week and warns you if an intense session falls in the middle of your fast (neither the time of the session nor the 150 minutes before it are in the window), if no meal is possible 1 to 2 hours after the session, or if a 5:2 light day falls on a training day. It then looks, in 15-minute steps between 07:00 and 13:00, for the nearest opening time that clears all the warnings, and suggests it to you.

On 5:2, the two light days are the two non-training days furthest apart from each other (Monday and Thursday if there aren't two).

Why this choice

• Trials comparing intermittent fasting with classic calorie restriction find comparable weight loss: it is an organisational tool, not a magic method. Hence a cautious build-up and low ceilings.
• The blocking situations are those where restricting meal times carries a real risk (growth, pregnancy, treatments, eating disorders, underweight).
• Placing the window around sessions lets you train fuelled and eat after exercise, which matters for recovery and for keeping muscle.

Limits

• The app shows no "metabolic stages" (ketosis at a given hour, autophagy…): these thresholds vary too much from one person to another to be announced.
• There is no timer for hours fasted, and no fast longer than 24 hours.
• Breaking the fast is not detected from your food diary.
• The health questions rely on your answers: they are no substitute for medical advice.

References

1. de Cabo R, Mattson MP. Effects of Intermittent Fasting on Health, Aging, and Disease. New England Journal of Medicine, 2019;381(26):2541-2551.
2. Lowe DA, Wu N, Rohdin-Bibby L, et al. Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity: The TREAT Randomized Clinical Trial. JAMA Internal Medicine, 2020;180(11):1491-1499.
3. Harvie MN, Pegington M, Mattson MP, et al. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women. International Journal of Obesity, 2011;35(5):714-727.