Dr Nick Fuller
Leading Obesity Expert at the University of Sydney and founder of Interval Weight Loss.
Weight loss injections like semaglutide, tirzepatide and liraglutide can feel like magic at first: your appetite drops, the scales move and your energy starts improving. But almost everyone eventually hits a point where progress slows or stops altogether. This weight loss plateau is frustrating, especially when studies show that medications like GLP-1 agonists can trigger 15 to 25 percent weight loss on average. So why does the weight suddenly stall?
The truth is, plateaus happen to almost everyone, even with medication. Weight loss plateaus aren’t you ‘failing’ at all; they’re your body slipping into self-protection mode. As the kilos drop, your metabolism and hormones reshuffle to help you conserve energy. Add changes in appetite, activity and hormones, and you’ve got the perfect recipe for a pause on the scales.
If you’re wondering why the injections have ‘stopped working’ or what you can do to get things moving again, keep reading. This guide breaks down the science and gives simple, realistic fixes that fit into everyday life.
A weight loss plateau is a period where your weight remains the same for several weeks despite continuing your routine. It’s not a sign of failure or that your medication has stopped working. It’s simply your body adapting to a lower caloric intake and smaller body size. Metabolic adaptation can kick in early, even as early as as a few weeks into weight loss, leading to a natural slowdown.
Plateaus also occur because your body becomes more efficient. As you shrink, you burn fewer calories doing the same activities, which means your previous habits don’t create the same calorie deficit as before. This is completely normal and expected.
Understanding this helps reframe plateaus from ‘I’m stuck’ to ‘my body is adjusting’—a much healthier mindset to move forward with.
If your progress has suddenly stalled, your metabolism may be adapting to your new routine. Read 10 Mistakes That Slow Down Your Metabolism to see if any of these common habits are holding you back.
Plateaus don’t just happen out of nowhere. Several underlying mechanisms contribute to the slowdown.
As body weight drops, your daily energy expenditure decreases. A lighter body simply needs less energy to function. Research shows that this reduction in calorie burn can be significant enough to halt weight loss temporarily.
When you eat less or feel fuller faster, you may unintentionally move less during the day. Even small reductions in non-exercise activity, like fidgeting or walking around the house, can influence calorie output.
Metabolic adaptation is a protective mechanism. Your body tries to conserve energy when it detects sustained calorie reduction, making your metabolism temporarily slower.
Skipping meals, irregular eating patterns or fluctuating portion sizes can disrupt routine and affect appetite hormones, making weight loss less predictable.
While injections often reduce hunger, appetite may shift over time. For some people the strong appetite-blocking effect naturally softens, leading to slightly higher food intake without realising it.
Beyond biological changes, certain lifestyle and medication-related factors may contribute to hitting a plateau.
Your body may take time to adjust to new doses. As your system adapts, weight loss can temporarily slow, or even cause weight regain, even when you’re doing everything right.
If meals lack protein, fibre or essential nutrients, your body may respond with lower energy levels or subtle increases in hunger. Numerous studies highlight the importance of nutrient variety for long-term weight loss success.
Weight loss injections often reduce appetite and energy intake, which may unintentionally reduce movement throughout the day. Less movement means fewer calories burned.
Hormones like leptin, ghrelin and insulin change during weight loss. Drops in leptin, a hormone tied to fullness, can trigger increased hunger or slower metabolism.
Research consistently links poor sleep to reduced weight loss, higher cravings and impaired glucose regulation. Even one night of insufficient sleep can affect appetite hormones.
Plateaus are normal, and the good news is they’re usually fixable with small, realistic tweaks. These strategies help nudge your body back into a gentle deficit without extreme effort.
Boosting daily steps by even 1,000 can significantly increase calorie burn. Walking is one of the most accessible, low-stress ways to restart progress.
Protein supports fullness, muscle maintenance and steady blood sugar. Studies show that higher-protein diets can improve satiety and increase the thermic effect of food. Aim to add protein to each meal.
Better sleep helps regulate hunger hormones like leptin and ghrelin. Aiming for 7 or more hours may improve appetite control and energy levels.
We often underestimate intake without realising it. Tracking meals for a few days increases awareness and highlights patterns like portion creep, mindless snacking or low protein intake.
Dehydration can impair metabolism and increase hunger cues. Drinking enough water supports digestion, fullness and overall energy.
Some plateaus need medical guidance to rule out underlying issues or adjust treatment plans safely.
No progress for several weeks: If your weight hasn’t budged for more than four to six weeks despite consistent habits, professional support may help.
New or worsening symptoms: If nausea, bloating, headaches or fatigue intensify, speak to your provider to ensure the medication is still suitable.
Concerns about dosage: Your doctor may adjust your dose or timing if your progress has slowed or side effects appear.
Trouble managing appetite: If hunger returns strongly after initially dropping, this may indicate a need for dose evaluation or routine changes.
Noticeable side effects: Persistent or severe side effects should always be assessed to ensure safe continuation of treatment.
A weight loss plateau after injections is completely normal and happens to almost everyone. It doesn’t mean you’ve failed or that the medication has stopped working. It’s simply your body adapting.
With small tweaks like more steps, better sleep, higher protein and mindful tracking, most people overcome plateaus and continue progressing. And if you’re unsure, your healthcare team can help guide the next steps toward sustainable, healthy results.
Plateaus often happen when your body gets too used to the same patterns. Read 7 Signs You Have Slow Metabolism to understand whether metabolic slowdown is part of your plateau.
Dr Nick Fuller is the founder of Interval Weight Loss and is a leading obesity expert at the University of Sydney with a Ph.D. in Obesity Treatment. Dr Fuller is also the author of three best-selling books and his work been published in top ranked journals in the medical field, including JAMA, Lancet and American Journal of Clinical Nutrition.