Weight-loss injections are in the news everywhere, and many people in Chennai now ask us about them. They can help some people a great deal, but they are medicines, not a shortcut, and food still decides much of the result. Here is what a dietitian wants you to know before you start.
What these injections are
The best known are semaglutide and tirzepatide, given as a weekly injection under the skin. They copy gut hormones (GLP-1, and for tirzepatide also GIP) that tell the brain you are full and slow down how fast the stomach empties, so people feel less hungry and eat less. Both are now sold in India on prescription.
What the studies show
- In the STEP 1 trial, adults with overweight or obesity who took semaglutide 2.4 mg a week for 68 weeks, with lifestyle advice, lost an average of 14.9% of their body weight, compared with 2.4% on placebo.
- In the SURMOUNT-1 trial, the highest dose of tirzepatide (15 mg) led to an average loss of about 21% over 72 weeks, compared with about 3% on placebo.
- In the STEP 1 extension, people who stopped semaglutide regained about two-thirds of the weight they had lost within a year.
These are averages from trials. Some people lose much more, some much less.
Who they are for
Doctors prescribe them for adults with obesity, or with overweight and a weight-related problem such as type 2 diabetes, high blood pressure or sleep apnoea, usually together with changes in diet and activity. They are not for pregnancy or breastfeeding, and some people with certain medical histories must not take them. Only your doctor can decide.
Common side effects
Nausea, vomiting, loose motions, constipation, bloating and feeling full quickly are common, especially when the dose goes up. Less often there are serious problems such as gallbladder or pancreas trouble. Tell your doctor about severe stomach pain or vomiting that does not stop.
Why food still matters
When you eat much less, it is easy to fall short of protein, iron, calcium, vitamin B12 and fibre. Fast weight loss can also take muscle with it. A dietitian helps you:
- Protect muscle: protein at every meal (dal, curd, paneer, eggs, fish, chicken), plus strength exercise
- Eat enough: small, nourishing meals instead of skipping food altogether
- Manage nausea: small portions eaten slowly, plain foods such as idli, curd rice or khichdi, less oily and fried food
- Prevent constipation: fluids through the day, vegetables, fruit and whole grains
- Keep blood sugar steady if you also take diabetes medicines (your doctor may change the dose)
What happens when you stop
Appetite usually comes back. Without new eating and activity habits, weight tends to return, as the STEP 1 extension showed. Use the months on treatment to learn portions, build a protein-rich routine with your own food and stay active, so you are ready when the dose is reduced or stopped.
Buy only with a prescription
In 2024 the World Health Organization warned about fake semaglutide found in several countries. Buy these medicines only with a prescription, from a licensed pharmacy, and never from social media or unknown websites.
Where a dietitian fits
Healthy Diet Studio, near Tambaram, Chennai, does not prescribe medicines. If you and your doctor decide on an injection, dietitian Bhuvana B can plan your meals around it and help you keep the weight off afterwards. If you would rather start without medicines, a dietitian-led weight loss program built on your home food is often the first step.
Sources
- Once-weekly semaglutide in adults with overweight or obesity (STEP 1), New England Journal of Medicine, 2021
- Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1), New England Journal of Medicine, 2022
- Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension, Diabetes, Obesity and Metabolism, 2022
- WHO issues warning on falsified medicines used for diabetes treatment and weight loss, World Health Organization, 2024
This article is general nutrition information, not medical advice. Talk to your doctor before changing your diet if you have a health condition or take medicines.
