Want to Cut Back on Meat? Studies Suggest a Flexible Approach Has More Staying Power

The recent and sweeping EAT Lancet report urges people across the globe to eat more plants and people in high-income countries to reduce their consumption of meat and dairy to protect human and planetary health. The researchers write that evolving the food system in this way could prevent 40,000 early deaths per day globally, and cut food-related emissions in half by 2050.

Strategies asking for moderate dietary changes may be more broadly appealing and sustainable over time than all-or-nothing approaches. Wide adoption of the report’s Planetary Health Diet would entail a two-thirds increase in fruit, vegetable and nut production, and for a one-third reduction in livestock meat production, globally compared to 2020 levels. In practice, it would mean people would consume only about one portion of red meat per week, two portions of poultry and fish per week, and one serving of dairy per day.

Do diets that allow for modest meat consumption actually stick better than fully no-meat diets? For Brian Kateman, president and co-founder of the Reducetarian Foundation, and author of the books Meat Me in the Middle and The Reducetarian Solution, the answer is clear: “There are a lot of studies that show that if you want something to be sustained for the long term, it’s not necessarily best to entirely transform one’s life,” he says. In his experience, once people begin reducing their meat intake, “they discover that it’s actually possible; it’s not the end of the world to go one day without animal products, or to go one meal per day without animal products. And they find themselves incrementally even enjoying the prospect of eating new foods or experiencing new cuisines.”

Let’s take a closer look at the science.

Flexible Diets Tend to Have More Staying Power

In the late 2010s, the Flexitarian Diet — eating mostly plant-based foods while occasionally consuming meat — gained steam as a practical and flexible approach to reduced meat eating. Its rise reflected growing public interest in the environmental and health-related impacts of diet, and in less rigid alternatives to veganism or vegetarianism. This and other plant-forward strategies have been embraced by some animal advocates looking to reduce the overall numbers of farm animals killed for food.

A number of studies have investigated which diet has the most staying power. In a 2021 study, scientists in Australia looked at four different reduced-meat diets to see if the less restrictive style resulted in longer term change than fully meatless diets. They randomly assigned 285 omnivorous participants to one of four diet regimes for one week: Vegetarian, Climatarian (limiting beef and lamb), One Step for Animals (eliminating chicken) or Reducetarian (reducing all meat). Participants were briefed on the diet requirements and also provided handouts with guidelines on what to eat, then were asked to use an app to record their meat intake each day. After one week of controlled dieting, the researchers tracked participants’ meat consumption and attitudes over the following three weeks.

Once the week of controlled dieting ended, all four groups continued to eat less meat than they had before the study, with no significant differences between groups. Participants who followed one of the less restrictive flexitarian plans maintained reductions just as well as those prescribed vegetarian diets, and vice versa. But admittedly, three weeks is not a very long follow-up time, and self-reported dietary data is not particularly reliable.

A 2023 study looked at a period of ten weeks instead of four weeks. The question was how well people stick to meat-reduction diets and how much they enjoy them. Researchers randomly assigned 80 young adults to one of two diets: a flexitarian plan that allowed three servings of red meat per week, or a vegetarian plan built around plant-based meat alternatives such as veggie burgers or sausages. The researchers provided meal kits and recipe instructions to participants in both groups. For ten weeks, the participants used an app to log their meals and complete questionnaires on enjoyment and satisfaction.

In this second study, by contrast, participants in the flexitarian group stuck to their diet more closely. Their average adherence score was 96, compared to 87 in the vegetarian group, whose compliance began to drop noticeably after week seven. Flexitarian participants also reported greater satisfaction with their diet and eating experience. Notably, both groups stuck to their diets fairly well, increased their vegetable intake and reported more positive feelings about eating in general. The researchers concluded that diets that allow some red meat may be easier for people to maintain.

For people wanting to shift their diet, “their relationship to animal products does not have to be all or nothing,” says Kateman. “They can simply cut back 10 or 20 percent or 30 percent. They can do Meatless Monday or weekday vegetarian or Vegan Before Six — all these different strategies centered around reducing.” When people try these types of less intimidating approaches, Kateman says, “there’s a lot of imagined fear that I think starts to slowly dissipate.”

Support and Timing Also Matter

While the particulars of the diet matters, timing and opportunity also play a role. Research suggests that age and structural support can shape how people adopt and maintain reduced-meat eating patterns. Younger adults, in particular, may be more open to trying flexitarian or plant-forward diets, especially during times of transition or newfound independence.

For example, one study, published this month in PLOS Climate, followed 402 psychology students and other young people from the UK and found that starting university and the beginning of the Covid pandemic — both significant “moments of change” — were often also times of dietary and other pro-environmental behavior change. More than 85 percent of the participants were female. Participants completed questionnaires about their pro-environmental behaviors, including reduced meat consumption.

When young people start university, they often “have a lot more freedom to make consumption choices,” explains Lorraine Whitmarsh, a psychologist and environmental scientist at the University of Bath and one of the study’s co-authors. “So they’re able to express their identity through those choices that they might not have been able to do when they were living in the parental home.”

Though the researchers recognize the limitations of self-reported data, they did find that young people who placed a stronger value on caring for others and the environment, or “self-transcendent” values, were significantly more likely to eat less meat after starting university and after the Covid pandemic began.

Whitmarsh explains that it is difficult to get people to change behaviors, such as dietary habits, “unless something happens to significantly disrupt those habits,” she says. “That’s why we’re interested in these moments of change, because they are usually quite natural moments at which the context around you changes.”

After such life changes, there’s a “critical window of opportunity,” Whitmore adds, “in which the new habits are not yet established” when people are more open to new information and behaviors. During this time, she says interventions like sharing information about “the health or sustainability benefits of a low-carbon diet,” or offering small incentives such as discounts at plant-based restaurants, are more likely to work. Once habits settle, she adds, people are far less receptive to these kinds of nudges.

The Bottom Line

Research shows that reduced meat diets may be easier to stick to for longer periods than fully meatless plans, and that significant moments of change, including starting university, may be particularly ripe for behaviour changes to diet. Research also shows that these modest shifts – eating less meat and more plants – can add up to significant change for the health of humans and the planet. As the latest EAT Lancet report underscores, meaningful dietary change on a global scale depends not on perfection, but on participation, and on building a food culture where eating mostly plants is not considered a sacrifice. “Every plant-based meal is one that’s worthy of celebration,” Kateman says.

As Americans are now eating more meat than ever before, with that number only predicted to go up, Kateman says these incremental changes are crucial: “Every possible reduction, no matter how small, has benefits.”