Fat loss app: the Definir goal, with clear limits
A good fat loss app does not promise numbers. It gives you a moderate deficit, helps preserve your muscle and adjusts with real data. Here is how the Definir goal in Elvyfit works, what the code decides at each step and which limits keep you from going too far.
What the Definir goal is and how it helps you lose fat
Elvyfit has four goals: Ganar músculo, Definir, Recomposición and Mantenerme. The app itself is in Spanish, so these are the names you will see. Definir is the fat loss goal, and it rests on a moderate calorie deficit: eating a bit less than you burn, while you keep strength training and getting enough protein.
There is no plain «lose weight» label: the app offers Definir. What matters is not only that the scale goes down, but that what goes down is fat and not muscle. That is why the goal combines nutrition, training and tracking, and why it does not promise how much or how fast.
How it really works: what the code decides
The Definir plan is calculated by code, not by a language model. These are the steps, and the full calculation is on the AI nutrition plan page.
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You pick a goal and a pace
You choose Definir, your target weight and the weekly pace that feels reasonable to you.
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The code sets the deficit
It starts from your energy use and applies a moderate deficit, always inside the safety limits.
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It splits your macros
Protein at 1.6 g per kg of body weight to help preserve muscle, fat at 0.4 g per kg and the rest in carbs.
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It builds your training
The strength routine is generated with rules, based on your days, level and equipment.
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You check in every week
The weekly report compares your trend with the expected pace and, if needed, suggests an adjustment.
A moderate deficit with a ceiling
The pace of loss is not a target you must hit. It is a ceiling the code will not let you pass. The more aggressive a deficit is, the easier it is to lose muscle, feel hungry and quit.
| Rule | Value | What it is for |
|---|---|---|
| Maximum pace | 0.5 to 1% of body weight per week | Avoid abrupt cuts |
| Maximum deficit | 25% of your energy use | Leave room to train and recover |
| Calorie floor | Never below the higher of your basal metabolism and 1,500 kcal (men) or 1,200 kcal (women) | Protect your health |
| BMI under 18.5 | Maintenance is forced | Avoid losing weight with little margin |
| Protein | 1.6 g per kg of body weight | Help preserve muscle |
The calorie floor cannot be changed, either by hand or by asking Elvy.
Why you keep lifting while you cut
In general, lifting weights is the signal that tells your body to hold on to muscle when you eat less. That is why Definir does not send you to do cardio only. It generates a strength routine, and the personalized gym routines adapt to your days, your level and your equipment.
A good indicator here is not how much you weigh, but whether you keep your loads. The workout tracker app shows you, set by set, whether you repeat or beat your numbers against the previous session. If they hold while your weight trend goes down, that is usually a good sign.
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Strength
A routine with progressive overload, and warm up sets that do not count toward your records.
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Steps
You can read your steps from Apple Health or Health Connect, in read only mode.
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Water
A target of 35 ml per kg, between 2 and 4 liters, with quick logging.
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Consistency
A streak that tolerates rest days and warns you without guilt if you are about to lose it.
How to read progress without obsessing over the scale
Your weight goes up and down on any given day because of water, salt or digestion. Elvyfit shows you the weight trend, not the daily noise, and the weekly adjustment needs 4 weigh ins per week before it acts.
To look beyond the scale you have body measurements, photos with a calendar and a comparison tool, and a body fat percentage from the Navy method that always appears as a range, with a typical error of 3.5%. All of it lives in fitness progress tracking with photos. A range is more honest than a number that looks exact.
Protections so fat loss does not get out of hand
Before your plan is generated there is a health screening of 7 questions, plus a confirmation of adult age, pregnancy, breastfeeding and eating disorders. If you are under 18 you cannot create an account. With pregnancy, breastfeeding or an eating disorder, nutrition stays at maintenance and you are pointed to a professional.
On top of that, the weekly adjustment pauses when there are signs of disordered eating, and a detector based on rules and text patterns intercepts messages where it recognizes extreme dieting or compulsive exercise, answering with a fixed text and help resources. It may miss unusual wording and does not replace professional help.
Honest limits of a fat loss app
Elvyfit cannot tell you how much fat you will lose or how long it will take, because that depends on your body, your history, your sleep and your consistency. It is not a medical product and does not replace a doctor or a registered dietitian. If you have a medical condition, take medication or have had an eating disorder, talk to a professional first.
The calculations are estimates. And if consistency is what you struggle with most, the workout streak can help you more than any fine tuning.
Frequently asked questions
What is the Definir goal in Elvyfit?
It is the fat loss goal. It applies a moderate calorie deficit, keeps protein at 1.6 g per kg of body weight and generates a strength routine. It is one of the four goals in the app, along with Ganar músculo, Recomposición and Mantenerme.
How big is the calorie deficit, and can I make it more aggressive?
The maximum deficit is 25%, and the pace of loss is limited to between 0.5 and 1% of body weight per week. There is also a calorie floor that cannot be changed. These limits cannot be bypassed, either by hand or through Elvy.
Will the app tell me how much fat I will lose?
No. There are no timelines and no promises, because nobody can honestly promise them. What you do see is your weight trend, your measurements, your photos and an estimated body fat percentage as a range, so you can judge your own progress.
Do I need a gym to use Definir?
No. When you create your profile you choose whether you train at a gym, at home or both, and what equipment you have, including body weight only. Your routine is built from that. Strength training is still a key part of the goal.
What health data does the app store about me?
From the health screening, only the result, the date and the version are stored, never your answers. Health data is used only with your explicit consent, it is not sold, and you can export or delete it from the app.
Is fat loss with Elvyfit free?
The Definir goal, the basic diet, the shopping list, workout logging and the weight trend are on the Free plan. Plus costs €19.99 a month or €199.99 a year, with 7 days of trial without a card, and adds unlimited adjustments and five variants per meal.
Is the app available in English?
Not yet. The app is only in Spanish from Spain for now. The calculation rules are identical for all users, and this website is also in English so you can read how it works before you download it.
Cut with a plan that looks after you
Download Elvyfit, choose Definir and get a plan with a moderate deficit and strength training.