Fitiva
Losing weight with a personal trainer
What is realistic in twelve weeks, what a coach really does along the way and how to spot a dubious offer. No miracles, just numbers that hold up, with the sources to back them.
Contents9 sections
What is realistic in twelve weeks
If you want to keep your muscle while losing weight, don't lose too fast. A widely cited review for strength athletes recommends a pace of about 0.5 to 1% of body weight per week. At 90 kilos, that is roughly 0.45 to 0.9 kilos a week, so about 5 to 10 kilos over twelve weeks.
Sources: Helms et al., Journal of the International Society of Sports Nutrition, 2014 and S3-Leitlinie Prävention und Therapie der Adipositas (the German guideline on preventing and treating obesity), October 2024.
Anyone who promises you much more usually means water and muscle, and the kilos come back quickly after the programme. If you lose less, you have often still won: strength, sleep and fitness usually improve before the number on the scales moves.
The four levers that count
- A moderate calorie deficit. The German obesity guideline gives 500 to 600 kilocalories a day below what you burn as a guide value. More is not better, you just can't keep it up as long. Our glossary explains exactly what a calorie deficit is.
- Enough protein. An analysis of 49 studies found that with strength training, more than about 1.6 grams of protein per kilogram of body weight a day brings hardly any extra muscle. If you want to play it safe, the authors say you can go up to 2.2 grams. Protein protects your muscles in a deficit and keeps you full.
- Strength training, two or three times a week. It tells your body which mass to keep. The WHO recommends that adults do strengthening exercises for all major muscle groups on at least two days a week. Cardio helps with the deficit but does not replace strength training.
- Movement in everyday life. Steps add up over the day and are easier to stick with than extra sessions. An analysis of 15 studies with more than 47,000 adults found the biggest health benefit at 8,000 to 10,000 steps a day, and from age 60 already at 6,000 to 8,000.
Not medical advice. These figures are recognised recommendations, not a diagnosis. If you have a pre-existing condition, take medication or are pregnant, talk to your doctor first.
What a coach really does
Not shout at you. When it comes to losing weight, a good coach mainly does four things.
- They measure. Your weight several times a week, reviewed as a weekly average, plus body measurements and photos every four weeks. The scales alone will mislead you, because water fluctuates from day to day.
- They write a training plan you can manage. Two or three strength sessions that fit into your week, with clear progression. What makes a good plan is covered in the article Getting a training plan made.
- They sort out your eating without dictating it. Two changes are usually enough: more protein, fewer calories from drinks and snacks. A food diary for two to four weeks shows where to start, as described in the article Tracking food without obsessing over calories.
- They keep you on track in the check in. The fixed weekly appointment is often the real reason people stick with it when they have a coach, and don't when they don't.
When progress stalls
After a few weeks, weight loss almost always slows down. That is normal: your body gets lighter, burns less and also turns its energy use down. The guideline describes exactly this effect and expects a new balance after three to six months. A good coach then checks, in this order:
- Is everything really being logged, at weekends too and drinks too?
- Are sleep and stress in order?
- Is there enough protein?
Only then do they adjust the deficit, and in small steps. Anyone who doubles their training and halves their food instead loses muscle and motivation and is back at square one a few weeks later.
What it costs
A weight loss package usually consists of a plan, check ins and being able to reach your coach, often with one in-person session a week or every two weeks. Work out the price per month with everything that comes with it, not the single hour.
Model 1
Package with in-person sessions
Plan, check ins and regular sessions with your coach. The most expensive option, but your technique gets dialled in, and the fixed appointment keeps you on track.
Model 2
Online coaching
Plan, weekly review and chat, with no in-person sessions. Much cheaper, and a good fit for weight loss if your strength training technique is already solid.
Model 3
Hybrid
An in-person session now and then for technique and motivation, with online coaching in between. A good middle ground for many people.
The usual prices and how to compare offers fairly are in the article What does personal training cost?.
Warning signs
With offers like these, keep looking:
- Promises like ten kilos in four weeks.
- Plans with 1,200 kilocalories a day or less, without a doctor supervising you. The guideline requires medical supervision for diets that low.
- Shakes, capsules or detox products you are supposed to buy as part of the programme.
- No strength training in the plan.
- Not a word about life after the programme.
How to find the right coach
Look for coaches who combine weight loss with strength training and talk about your everyday life rather than about discipline. Ask for examples of people in your situation. More questions for the first conversation are in the article Finding a personal trainer: 7 questions.
In Fitiva you find coaches on the map, by city and focus. Their profile shows qualifications, packages and prices before you book, and you pay online or in person. At launch, coaches and events are in Germany, Austria and Switzerland.
You don't need a coach to start tracking. You log your food for free with one sentence to Ava, plus weight, body fat and progress photos, and the energy balance shows you every day whether you are in a deficit. If you connect with a coach later, they see your meals, workouts and weight, without screenshots. The preview in three questions shows you what a week with your goal could look like.
In short
- A realistic pace is about 0.5 to 1% of body weight per week.
- Four levers: a moderate deficit, enough protein, strength training and steps.
- Your coach measures, plans, sorts out your eating and keeps you on track in the check in.
- When progress stalls, that is normal. You fix it in small steps.
- Steer clear of miracle promises, crash diets and product sales.
Frequently asked questions about losing weight with a coach
How much weight can I lose in a month?
At about 0.5 to 1% of your body weight per week, that is roughly 1.5 to 3 kilos in four weeks if you weigh 80 kilos. In the first few days you often lose more, but that is mostly water.
Do I have to count calories to lose weight?
No, but you need a deficit, and the easiest way to see it is to write down what you eat for a while. Two to four weeks is usually enough. How to do that without chasing numbers is in the article Tracking food without obsessing over calories.
Is cardio enough to lose weight?
It helps with the deficit, but it does not protect your muscles. For that you need strength training, on at least two days a week as the WHO recommends.
What does a personal trainer for weight loss cost?
Every coach sets their own price. Which models exist and what range the Bundesverband Personal Training (the German federal association for personal trainers) gives are in the article What does personal training cost?. In Fitiva you see the price in the profile before you book.
Can I lose weight with Fitiva without a coach?
Yes. You track food, training, weight and progress photos for free, and Ava helps you along. If you want support later, you find your coach in the same app, and your data is already there.
