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  • Writer's pictureRenee Little, R.D.

What you need to know if you're on or are contemplating weight loss medications

I'm not sure if you've noticed but weight loss medications have been in social media a lot lately with speculation about celebrities taking them and some have been approved for use in the US and Canada for public use. You may be thinking...."but you are a weight inclusive dietitian, why are you talking about weight loss medications?"

The reasons why I'm writing this post include:

  1. Helping you make an informed decision - these drugs are approved by Health Canada and have reached a fairly widespread use. There is a lot of risks and "need to know" information that I'm not seeing communicated well across social and media platforms. In order to make a true informed decision you need to know all the facts.

  2. It's important to understand the risks/ side effects - know what to expect, what to watch for and know how to discuss making a screening and follow-up plan with your physician.

  3. Know that you don't have to live with side effects (and shouldn't) - even though side effects are common you should not be expected to live with them. Know that your physician, pharmacist and a dietitian can support you while you are taking these drugs.

Please know, I am not promoting the use of these medication, nor am I passing judgement on those who choose to take them. As a dietitian who follows a weight inclusive approach I have the utmost compassion for those seeking intentional weight loss.

I do not want you to choose these medications or continue with them in spite of the risks and side effects because of the magic bullet promise of weight loss. A true informed decision making process takes time and knowledge sharing. It takes effort on the part of both yourself and the medical professionals supporting you.

What are the weight loss medications approved for use in Canada?

This is a list of the medications approved for use in Canada for weight loss purposes:

1. Liriglutide (brand name Victoza or Saxenda)

2. Naltrexone/Bupropion (brand name Contrave)

3. Semaglutide (brand name Wegovy or Ozempic)

4. Orlistat (brand name Xenical)

The first three medications are relatively new with their approval for weight loss in Canada.

Approval dates include: Liriglutide Feb 2015, Contrave March 2015, Semaglutide in November 2021 and Orlistat has been approved since 1999.

Making an informed decision & seek support for side effects

When you are making a choice for your health, it's important to have all the information needed in order to make an informed decision. If you are considering these medications it's easy to get wrapped up in the "success" stories you are seeing on TikTok or Instagram or hearing from friends/ family. It is similar to dieting in that we only hear about the good parts.

In order to make an informed decision for yourself, it's important to review the risks and side effects of the medication(s) you are considering. If you are already on the medication or just starting review these data sheets to know what side effects to expect and watch out for. Know that any adverse effects warrant further discussion with your physician and/or pharmacist.

You can read the product monographs here:

Liriglutide - page 8 and 9

Contrave - page 4 and 14

Semaglutide - page 4, 5, 8

Orlistat - page 4

If you have more questions from reviewing the product monograph, I would encourage you to print it out and bring it to an appointment with your pharmacist or doctor to discuss further. It can be helpful to know what screening and monitoring processes are in place (i.e. labs, how often follow-up is required). Some of the side effects listed are more common and others less common.

What side effects can a dietitian support you with?

If you do experience side effects you should always report these to your doctor and pharmacist. One of the issues could be that the medication is at too high of a dose or not appropriate for your body at this time. It's also good to check in to make sure you are following the most optimal administration schedule to minimize side effects.

Commonly reported side effects which a dietitian can support you with include:

  • nausea

  • suppression of appetite with low food intake

  • low blood glucose

  • severe and rapid weight loss

If you are taking these medications for weight loss purposes you may be thinking...."But I want my appetite to be else am I supposed to lose weight?" Yes, I understand your goal is weight loss however, this should not take place at the expense of achieving an adequate level of nutrition day to day. There is a baseline of macro (carbs, protein, fat) and micro (vitamins, minerals) nutrients that each one of us need day to day to stay healthy and well.


This is one of the most common side effects reported for both Contrave and Saxenda. If your nausea is severe and you are not able to eat/ drink consistently please speak to your pharmacist and physician promptly (do not wait). If you are having nausea, have spoke to your physician/ pharmacist and they recommend continuing with your medication a dietitian can help you to reduce nausea and improve food and fluid intake.

Suppression of appetite and food intake

In order to meet your basic nutrition needs, you do need to eat enough food throughout the day. You may be excited that your seeing lower food intake with this medication because you are desiring weight loss which can make it less likely to see this as a risk.

It's important to remember that if you are not meeting your basic needs this can increase fatigue, impair sleep, reduce muscle mass/ strength, deplete vitamin/ mineral stores, reduce bone density and increase risk of hypoglycemia. A dietitian can help you to plan your meals to ensure you are eating adequately and getting the nutrition you need throughout the day despite having a low appetite.

Low Blood Glucose

This can be a side effect of Liraglutide ( brand Victoza). It is a medication which is also used to treat type 2 diabetes. Hypoglycemia or low blood glucose could be an indication this medication or the dose might not be a good fit for you (speak to your doctor and/or pharmacist). It can also be an indication you are not eating enough, often enough or not having balanced meals/ snacks. A dietitian can help to support you in assessing if your diet could be more supportive in preventing low blood glucose and help you to put that into place.

Severe and rapid weight loss

If you are trying to achieve weight loss you might be really excited to see the weight on the scale going down every week or day. If you are losing weight rapidly or having large numbers of weight loss over time be sure to connect with your pharmacist and/or doctor to discuss and review your treatment plan.

There is a caution with rapid and severe weight loss that I want to bring to light as it can cause malnutrition related concerns. It is one indication that you may not be meeting your nutritional needs and there may be vitamin/ mineral stores depletion.

How can a dietitian help?

A dietitian can assess if you are meeting your needs and if you are not can support you to take steps towards adequate nutrition. As an example of how a dietitian would support you is an assessment and support with the following:

  • Adequate protein intake - if you are not meeting your protein needs then you could lose more muscle mass during weight loss.

  • Adequate fat intake - low intakes of fat can deplete calories too severely and will impact your ability to absorb fat soluble vitamins and minerals.

  • Adequate carbohydrates intake - skipping out on carbohydrates can cause fatigue, low blood sugars, poor movement recovery, poor sleep and irritability.

  • Review of key vitamins and minerals specifically pertaining to bone health as rapid weight loss both may negatively impact bone density.

Having an eating disorder is a contraindication to weight loss medications

If you have a diagnosed or undiagnosed eating disorder or feel your eating is restrictive and causing stress in your life these medications are not for you. In the discussions with your doctor if these medications are recommended please disclose your history of an eating disorder, disordered eating or restrictive eating.

Making an informed decision & staying as well nourished as possible

Overall I hope this information will allow you to make a more informed decision on if this medication is a good fit for you or not. I also hope that it will allow you to have better discussions with your medical professionals and to recognize side effects and seek support.

If you have any side effects this should be communicated to your physician and pharmacist. If the decision is to carry on with the medication in spite of the side effects, a Registered Dietitian can support you to maximize your nutrition and minimize the impacts of the adverse effects.


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