Taking part in research: 15 months of coaching

That works out at €2.84 per day. Weight loss coaching for 15 months instead of 12, for the same €1,295: according to Overgewicht Nederland B.V., that is what you get if you take part in their research into vitamin and mineral supplementation. You get three extensive measurement sessions in Amersfoort. Half of the participants get a placebo. Here you can read in plain language what that means, so you can make a good choice.

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Who does what: Overgewicht Nederland B.V. in Amersfoort provides the coaching; through the form you give your details to them. Price information from the provider, reference date 21-10-2026. See also about this site and the programme.

What the research programme with 15 months of coaching involves

The research programme is a variant of the regular coaching programme. You get the same coaching, but for 15 months instead of 12. On top of that come three extensive measurement sessions in Amersfoort. In return, you take part in a scientific study into vitamin and mineral supplementation. Supplementation means: taking extra vitamins and minerals, for example as a tablet.

Nobody knows in advance what that supplementation does. That is exactly why it is being researched. So do not assume that it will make you lose weight faster or feel better. This page makes no promises about that either.

Want to know first what the regular programme involves? Then read the explanation of 12 months of weight loss coaching. The research programme is a separate form of it, with different arrangements.

Placebo and drawing lots: how this coaching research works

In the research, participants are divided into two groups. In placebo research this is usually done by drawing lots: you do not choose, and neither do the researchers. Exactly how it works in this study is set out in the participant information.

• One half gets the real vitamins and minerals.
• The other half gets a placebo. That is a dummy product that looks the same but contains no active substance.

Usually you do not know which group you are in. Why so complicated? Because people often already feel different when they think they are getting something. By giving one group a dummy product, researchers can see whether the difference is really due to the vitamins and minerals, or to something else. Without a placebo group, the outcome says little.

For you this means: you get the coaching and the measurements either way. Only the supplement differs, and you usually do not know which one you have.

The three measurement sessions of the research programme

During the programme you come to Amersfoort three times for an extensive measurement. According to Overgewicht Nederland B.V., each measurement session includes these components. Exactly when the measurement sessions take place, you will hear from the researchers.

Components of a measurement session. Source: Overgewicht Nederland B.V., programme information (21-10-2026); explanation of REE and InBody: see sources.

Measurement	What it measures
REE measurement	Your energy use at rest
InBody	Estimate of fat and muscle
Blood tests	Values in your blood
Blood pressure	Your blood pressure

The REE measurement

REE stands for your resting energy expenditure: how much energy your body uses when you are doing nothing. It is measured with indirect calorimetry. The device measures how much oxygen you breathe in and how much carbon dioxide you breathe out, and uses this to calculate your energy use (LITFL, 03-11-2020). A short snapshot is less reliable than a longer measurement. You can read more in all about the REE measurement in Amersfoort.

The InBody measurement

An InBody uses a weak electrical current to estimate how much fat and muscle you have. Compared with a DEXA scan, this estimate is not exact and is often too low (Merrigan et al., 2022). An InBody is mainly useful for following your own progress, measured under the same conditions. Read more in the InBody measurement and DEXA.

Preparation

For a REE measurement you often have to come fasting. The Jeroen Bosch Ziekenhuis, for example, asks for 8 hours of fasting (water is allowed), no strenuous exercise beforehand and no smoking for 2 hours. That is that hospital's protocol. The researchers will give you their own instructions, and you follow those.

What the coaching gives you, even in the placebo group

An honest question: is taking part worthwhile if you may only get a dummy product? According to Overgewicht Nederland B.V., the extra measurements are of great value for the coaching even without active supplementation. That makes sense when you look at what you get:

• Three months of extra coaching. 15 instead of 12 months, for the same amount.
• Three times an extensive picture of your body. Your coach can tailor their advice to your measured energy use at rest and to how your fat and muscle change.
• Blood values and blood pressure. Extra information about your health. Questions about results are discussed with the researchers or your GP (huisarts).
• A contribution to knowledge. By taking part, you help find out whether supplementation does anything for people with overweight.

Also know what it asks of you: three trips to Amersfoort, following the instructions, and taking the supplement as agreed. If you live further away, consider whether the journey is feasible for you. On the page about obesity care around Amersfoort you can read more about the region.

Approval, voluntary participation and the participant information

According to the provider, the research has been approved by a METC. That is a medical research ethics committee (medisch-ethische toetsingscommissie): an independent committee that assesses medical-scientific research involving people in advance.

Two things apply to every medical-scientific study that falls under the Medical Research Involving Human Subjects Act (Wet medisch-wetenschappelijk onderzoek met mensen, WMO):

• Taking part is voluntary. You decide for yourself whether you take part. You can also stop later, without having to explain why.
• You receive written information first. Before you sign, you receive the official participant information from the researchers. It sets out what the research involves, what is asked of you and what the risks are. You can read it calmly and ask questions about it.

Really read that information, and discuss it with someone you trust or with your GP (huisarts) if you are in doubt. If you take medication or have a condition, also ask whether you can take part. What happens to your payment and coaching if you stop the research, ask before you sign.

Costs of the research programme and the other coaching options

About €2.84 per day. According to Overgewicht Nederland B.V., the research programme costs €1,295 for 15 months. That works out at €86.33 per month. How you pay, you will hear in the introductory meeting. Below you can see all the options side by side.

Amounts according to Overgewicht Nederland B.V., reference date 21-10-2026. The price per day is a conversion (total divided by the number of days in the term); you pay per month or per year. Medication comes on top. You will receive the exact terms, such as the term and cancellation, in writing before you start.

Torn between the research and the regular programme? The regular programme is shorter and without research. The research programme is longer and cheaper per month, but asks more of you. There is no right or wrong choice, only a choice that suits you.

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What are you signing up for? *12-month programme, €3.55 per day (€108 per month)12-month programme, €3.55 per day (€1,295 per year)15-month research programme, €2.84 per dayExtra personal support (a conversation first)I don't know yet, call me first

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How Overgewicht Nederland compares with Goodweigh, Wellis and Yazen

How Overgewicht Nederland compares with Goodweigh, Wellis and Yazen

What do you get?	Overgewicht NederlandOverg. NL	GoodweighGood­weigh	WellisWellis	YazenYazen
Consultation with a doctor by phone or video	✓Yes:	✗No:	Partly:	–Not mentioned:
Psycho­logist in the team	✓Yes:	–Not mentioned:	–Not mentioned:	✓Yes:
Price of the coaching on the site	✓Yes:	✓Yes:	–Not mentioned:	✓Yes:
Everything via chat, without phone calls	✗No:	✓Yes:	✓Yes:	Partly:

✓ yes ✗ no (according to the provider itself) partly – not mentioned. Reference date 22-10-2026. Compare for yourself with the decision aid

Torn between this programme and the regular programme? Then read the comparison with Yazen, which also does blood tests.

Frequently asked questions about the research programme

What does the research into vitamin and mineral supplementation involve?

You get 15 months of coaching and three extensive measurements in Amersfoort, and you take a supplement. Half of the participants get real vitamins and minerals, the other half a placebo. This allows researchers to see whether supplementation has any effect. The details are in the participant information you receive before signing.

What is a placebo in medical research?

A placebo is a dummy product. It looks the same as the real product, but contains no active substance. Researchers use it for comparison. If the group with the real product feels different from the placebo group, that is probably due to the product, and not to the idea that you are getting something.

Can I choose whether I get the real vitamins or the placebo?

No. In placebo research, the group is usually decided by drawing lots and you do not know which group you are in; the details are in the participant information. That is necessary to make a fair comparison. If you want to be sure you will not get a dummy product, the regular 12-month programme suits you better.

Is taking part worthwhile if I am in the placebo group?

According to Overgewicht Nederland B.V., yes: the extra measurements are of great value for the coaching even without active supplementation. Either way, you get 15 months of coaching, three REE measurements, InBody, blood tests and blood pressure measurements. Only the supplement differs. Read more about what an InBody measurement shows.

What happens during a measurement session in the research?

According to the provider, your energy use at rest is measured with a REE measurement, your fat and muscle with an InBody, blood is taken and your blood pressure is measured. This happens three times during the programme, in Amersfoort. How long a measurement session takes and how to prepare, you will hear from the researchers.

What is a METC and why is approval important?

A METC is a medical research ethics committee (medisch-ethische toetsingscommissie). Such a committee assesses in advance whether medical-scientific research involving people has been set up carefully. According to the provider, a METC has approved this research. Approval does not mean that the supplement works, but that the design has been independently assessed in advance.

Can I stop taking part in the research?

Yes. In medical-scientific research involving people, taking part is voluntary and as a rule you can stop without saying why; how that works here is set out in the participant information. Do ask before you sign what stopping means for your coaching and your payment. That is not on this site, and it is good to know it in advance.

Why do you get 15 months for the same price in the research programme?

Per day: €3.55. According to Overgewicht Nederland B.V., the research programme costs €1,295, the same as the regular programme per year, but it lasts 15 instead of 12 months. In return, you take part in the research and come to Amersfoort three times for measurements. That way both parties benefit.

What do you call people who take part in research?

People who take part in medical-scientific research are called research subjects or participants. In this programme you are both: you get 15 months of coaching and you take part in the research into vitamin and mineral supplementation. As a research subject, you receive written information in advance and give your own consent. If you want to know how to prepare for the measurements, read the preparation for a REE measurement.

Can I take part in the research if I take medication?

That is not on this site. Every study has its own rules about who can and cannot take part. They are in the participant information. Mention your medication in the first phone call. If in doubt, consult your GP (huisarts). If you use a GLP-1 medicine, also read about coaching alongside GLP-1 medication.

How do you become a participant in medical research?

You sign up with the researchers, receive written information and only sign once you have understood everything. With this programme it starts with the form, followed by a phone call. The participant information sets out who can take part, what is asked of you and what the risks are. Take the time to read it calmly and ask your questions before you sign. Also read how signing up for coaching works.

Do you get paid for taking part in medical research?

Not in this research: you pay yourself, but you get coaching for longer. That works out at €3.55 per day. According to Overgewicht Nederland B.V., the programme costs €1,295, the same as one year of the regular programme, and lasts 15 instead of 12 months. In other studies, whether you receive a payment and how much it is varies. So no fixed amount can be given; it is always stated in the participant information of the study itself.

Can I take part if I am already participating in another medical study?

That depends on the rules of this study, and they are in the participant information. Often you cannot take part in two studies at the same time, because the outcomes could then influence each other. So always mention another study in the first phone call, even if it is nearly finished. You will then hear whether taking part is possible, or whether the regular 12-month programme suits you better.

Why is research being done into vitamins in overweight?

The aim is to find out whether vitamin and mineral supplementation adds anything to weight loss coaching. You can only establish that fairly by comparing a group with the real supplement with a group that gets a placebo. Nothing is known on this site about the outcomes of this research. Exactly which questions the researchers want to answer is set out in the participant information. If you already take vitamins or supplements yourself, mention this in the first conversation.

Does this research take place in a hospital?

This research runs via Overgewicht Nederland B.V. and the measurements take place in Amersfoort. There, three times, your resting energy use is measured with a REE measurement, your body composition with an InBody, and your blood and blood pressure are tested. Medical research does not have to take place in a hospital to be carried out carefully; according to the provider, this research has been approved by a METC. You can read more about the area in obesity care in the Amersfoort region.

Sources

• Overgewicht Nederland B.V.: programme and price statement (21-10-2026)
• Postępy Żywienia Klinicznego: indirecte calorimetrie als gouden standaard voor REE (30-08-2023)
• LITFL: Indirect calorimetry (03-11-2020)
• Jeroen Bosch Ziekenhuis: Het meten van de ruststofwisseling (revision 15-07-2025)
• Merrigan et al.: InBody en DXA vergeleken, Journal of Exercise and Nutrition 2022;5(4):18 (2022)