The skinny on the weight loss jab
The notion of a silver bullet for weight loss is highly appealing. If you have a BMI of at least 30 and likely at least one other health concern such as diabetes or high blood pressure, under NICE guidelines you may soon be eligible to receive Semaglutide.
However, you need to go beyond the headlines to understand what it is, how it works, the risks and the alternatives from a nutritional therapy standpoint. Here is the low down.
What is it?
Glucagon-like peptide (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are hormones that are released naturally by the gut which jointly have an impact on the hormone insulin. GLP-1 and GIP agonists are drugs that work by mimicking the effects of these hormones. They started out as drugs to treat patients with type 2 diabetes (T2D) and act through simulating insulin release and inhibiting glucagon release.
The net effect is a lowering of blood glucose/improved glycemic control, but in T2D patients, other effects were noted – weight loss. We still don’t really have a clear explanation as to WHY the hormone is also increasing satiety and reducing appetite, but it is highly effective – hence the buzz and excitement.
Semaglutide is pure GLP-1 and is licensed for use as an obesity drug. The newer Tirzepatide is a combination of both GLP-1 and GIP and is currently only licensed for T2D, but is reportedly even more effective than Semaglutide, so expect to hear more about it in the future as a potential option for obesity should it become approved for use.
Semaglutide is administered weekly via an autoinjector pen requiring refrigeration and is known as Ozempic and Wegovy; the difference between the two is purely dose rates and branding. Tirzepatide is branded as Mounjaro and is administered in the same way.
Does it work?
It is extremely effective, but it comes with a large caveat.
In the original trial and its extension, weight loss was significant in all participants that begins to slow at around 60 weeks. As soon as treatment stopped at 68 weeks, there was an average two thirds regain in weight in all participants, but the amount of weight regained depended upon how much was lost originally. Those who lost 20% or more of body weight, regained some but not all. However those who lost 15% or less, ended up weighing more than their start weight at 120 weeks, hence its use for those who are genuinely obese.
Known Side Effects
Anything that changes things in the gut is going to have side effects. In trials these are noted as nausea, diarrhoea, vomiting, constipation, headaches, dyspepsia. However, these are noted as transient and can be managed well under medical supervision if the dose is slowly increased to minimise side effects. The reports of thyroid tumours in rodents were reported from a small trial of an earlier product Liraglutide, which is why GLP-1 agonists are not recommended for patients with certain thyroid conditions.
Anecdotal side effects
Peter Attia MD, based in the US has been using Semaglutide on patients for over two years. His observations are not in the trial data but he has noted:
A universal increase in resting heart rate by between 8 and 15 beats per minute (the majority of his clients use wearable fitness trackers). This sometimes corresponded with a lowering of heart rate variability but not in all cases.
A material loss of lean mass as well as fat mass – as much as a 1:1 ratio. Peter has his patients undertake a DEXA scan so he can monitor body composition. In the original trials only a small number of participants were DEXA scanned, so it was hard to draw any firm conclusions. The likely reason why the loss of lean mass is so great is that patients are unlikely to be getting adequate protein intake (protein is highly satiating). He has made a change in his practice and now instructs clients on Semaglutide to ensure they are getting their required protein intake daily.
What are the alternatives?
A good diet is about eating food which contain nutrients critical to satiety, but without over-eating in calories. If you are not getting enough nutrients, your body will naturally go in search of vitamins, minerals, essential fatty acids and amino acids you may lack by eating more.
Protein is the cornerstone of feeling full (many people on Semaglutide struggle to get adequate protein intake as they are just not hungry). Proteins are recognised as potent natural stimulators of GLP-1. A palm sized portion at every meal should be the mainstay of any diet, whether that be animal or plant based. The high amount of amino acids in protein also help to fuel the feel good ‘happy’ neurotransmitters. So, two eggs at breakfast or three tablespoons of chia seeds or a tub of natural yogurt. Lunch - canned sardines or some pulses in a soup and for dinner a portion of meat, fish, lentils or pulses. Whey protein is often used in studies for the stimulatory effect on GLP-1 secretion but make sure you get a good source.
The second thing that makes you feel full is fibre, so load up on veg and a little fruit – at least half the plate. There are some natural GLP-1 boosters for blood sugar management and satiety. These are avocado, cinnamon, curcumin, eggs, green tea, and rosemary. There are also certain supplements that have a similar action.
References
https://dom-pubs.onlinelibrary.wiley.com/doi/10.1111/dom.14725
https://pubmed.ncbi.nlm.nih.gov/34981502/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8235588/
https://joe.bioscientifica.com/view/journals/joe/221/1/T1.xml
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5148911/