As London Climate Action Week gets underway, the conversations dominating the agenda tend to involve renewable energy, carbon markets and sustainable infrastructure. Weight management medication is rarely on the list. Yet the rapid rise of GLP-1 receptor agonists, the class of drugs that includes semaglutide, sold as Ozempic and Wegovy, is beginning to redefine the eating habits of millions of people, and society’s eating habits have profound implications for the planet.
The recent approval of the first oral GLP-1 tablet in the UK removes one of the biggest practical barriers to uptake. With injectable GLP-1s already used by nearly 1.9 million adults in Great Britain, a figure that has nearly tripled in two years, oral formulations are likely to drive adoption to an entirely new scale. As these drugs become more accessible, their wider effects on the food system come into sharper focus.
Eating less, eating differently
It is well established that the most immediate effect of GLP-1 drugs is that users significantly reduce their food intake. A 2024 study from Cornell University found that households with at least one GLP-1 user reduced grocery spending by 5.3% within six months of adoption, rising to 8.2% in higher income households.
However, GLP-1 users are not simply eating less, they appear to be eating differently. The study also showed that the largest spending reductions were concentrated in calorie-dense, processed food categories, including a 10.1% decline in savoury snacks. A 2026 Guardian investigation found that more than half of GLP-1 users described their approach to eating as ‘mindful’, guided by hunger rather than habit. Three-quarters ate less chocolate, and 72% reduced their consumption of crisps. A Danish study analysing over 1.9 million supermarket receipts confirmed the broader pattern: after starting GLP-1 therapy, participants spent a larger share of their shopping on unprocessed foods and a smaller share on ultra-processed foods. Yoghurt was the only food category to record a statistically significant increase in spending.
There is, of course, a legitimate question about cause and effect. People who use GLP-1s are, by definition, engaged in active weight management, and some of the observed dietary improvements may reflect that broader motivation rather than the pharmacological effects of the drug itself. Nevertheless, there is a plausible biological mechanism. GLP-1 drugs have been found to slow gastric emptying and dampen hunger signals in ways that appear to alter the neurological drivers of cravings, particularly for high-fat and high-sugar foods, in a manner that willpower and dietary advice have historically struggled to replicate.
Why ultra-processed foods are a climate concern
The environmental significance of a shift away from ultra-processed foods (UPFs) is considerable. UPFs now account for over 70% of food sold in grocery stores in the UK and US, and represent more than half of total calorie consumption. Research published in Nature Sustainability found that, although UPFs represented just 19% of participants’ diets by weight, they contributed disproportionately to environmental pressures: 24% of diet-related greenhouse gas emissions, 23% of water use, 23% of land use, and 26% of energy demand.
This outsized footprint reflects the full lifecycle of ultra-processing: from extensive monoculture agriculture and high-energy manufacturing to long-distance supply chains and excessive packaging. A longitudinal study published in Science of the Total Environment found that participants who made substantial reductions in UPF consumption reduced their carbon footprint by 0.6 kg of CO₂ equivalent over the study period.
It is also worth noting that UPFs are, to a degree, engineered to undermine the very satiety signals that GLP-1 drugs seek to restore. Ultra-processed foods are known to suppress the effectiveness of key gut hormones — including the body’s own endogenous GLP-1 — that signal fullness, making overconsumption an almost predictable outcome. In that respect, GLP-1 drugs do not merely suppress appetite, they may be partially correcting a cycle of overconsumption that certain food products have, by design, helped to entrench.
The protein question
Were the story simply one of reduced consumption of calorie-dense, processed foods, the environmental case would be relatively straightforward. However, the picture is complicated by a concurrent shift in protein demand.
GLP-1 drugs produce significant weight loss, but a significant proportion of that loss, estimated at between 40% and 50%, can come from lean muscle mass rather than fat. To mitigate this, clinical guidance strongly recommends that GLP-1 users substantially increase their protein intake, typically to between 1.2 and 2.0 grams per kilogram of body weight per day, well above the standard dietary recommendation. The commercial consequences are already being felt. For example, the price of whey protein, derived from dairy, has risen fivefold in recent months as global demand has outpaced supply.
The environmental impact of this protein surge depends heavily on which protein sources consumers are actually turning to. On this point, the available evidence is somewhat reassuring. Multiple consumer surveys and market datasets suggest that GLP-1 users are gravitating away from red and processed meats and towards leaner alternatives: fresh poultry, fish, eggs, legumes, and lighter dairy products such as yoghurt. A study published in Food Quality and Preferences, surveying nearly 2,000 consumers, found that 45% of GLP-1 users reported eating less beef than before starting the medication. The likely mechanism is consistent with the drug’s known effects. By amplifying satiety signals and slowing gastric emptying, GLP-1s appear to make heavy, fatty foods — red meat, cold cuts, hard cheeses — less appealing.
From an environmental perspective, this directional shift is meaningful. Producing a kilogram of beef generates approximately 60 kg of greenhouse gas emissions; a kilogram of poultry generates around 6 kg. Dairy products sit at an intermediate level, though lighter formats such as yoghurt carry considerably lower footprints per unit of protein than hard cheese. Research published in Nature Climate Change has estimated that the worldwide adoption of a diet aligned with the EAT-Lancet planetary health diet, characterised by a shift from red meat towards legumes and nuts as principal protein sources, could reduce global annual dietary emissions by 17%. The dietary changes seen as a result of GLP-1 use appear to be moving in that more environmentally favourable direction.
Where the picture becomes more complicated
The food industry’s response to GLP-1 users has seen the proliferation of ‘GLP-1 friendly’ products, protein bars, fortified shakes, high-protein ready meals, which represents, in many cases, a new category of highly processed food. If users are substituting one form of processed consumption for another, the environmental benefit may be more limited than the headline shift away from snacks would suggest. The sustainability outcome appears to depend critically on whether increased protein density is genuinely replacing excess calorie consumption, or simply creating an additional category of demand.
It is important to position GLP-1-related dietary changes within a broader cultural context. The emphasis on protein consumption has become well established. Notably, the new US Dietary Guidelines, published in January 2026, have inverted the traditional food pyramid to place protein at its base, reflecting a wider societal shift in nutritional priorities. Separating the specific contribution of GLP-1 use from this wider trend is difficult. It should also be noted that most of the available evidence on what GLP-1 users actually eat is derived from consumer surveys and supermarket receipt data, rather than controlled clinical trials, and should be interpreted with the appropriate caution.
A disruption to the food system, not a climate intervention?
It would be overreaching to present GLP-1 drugs as a climate intervention. However, GLP-1 drugs are proving to be an undeniable disruptor of the food system, and one that is growing in scale and likely to grow further as oral formulations reduce the barriers to access. Meanwhile, research published in Nature Climate Change suggests that diet shifts represent one of the most powerful demand-side mechanisms available for reducing food-system emissions. It is clear that the food industry is already responding to the shift in consumer preferences, although whether that translates to a net positive environmental impact remains uncertain.
GLP-1 medications will not, on their own, deliver the scale of dietary transition that climate targets require. However, by reducing appetite for the food products most associated with overconsumption and environmental pressure — and by nudging both consumers and producers towards a greater emphasis on nutritional quality — they may be contributing to a more sustainable direction of travel.
Whether the shift in consumer habits is durable – particularly beyond the period of active medication use – and whether the commercial response from the food industry reinforces or diminishes the potential environmental benefit, remains to be seen. Nevertheless, particularly during London Climate Action Week when there have been numerous extreme heat weather warnings in the capital, it seems that the impact of GLP-1s on society’s eating habits and its wider environmental implications should form a part of the broader climate conversation.
