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Nutrition Professor Says a Sustainable Diet is a Healthier Diet

Kelsey Mangano: Add Variety, Cut Portions, and Sub Plant Proteins for Meat

Biomedical and Nutritional Sciences Asst. Prof. Kelsey Mangano
Assoc. Prof. Kelsey Mangano researches protein sources and gut health.

09/02/2021
By Katharine Webster

A sustainable diet is healthier for the planet – and for us, says Biomedical and Nutritional Sciences Assoc. Prof. Kelsey Mangano.

There are three keys to helping the environment while improving our own health, she says: Eat a wide variety of foods, cut portion sizes and food waste, and substitute plant proteins for some animal proteins.

College is the perfect place to do it, since the dining halls offer a range of choices, from fruit and salad bars to vegetarian and vegan entrees, she says.

“Variety in our choices is going to be the most beneficial, and listening to our hunger cues,” she says. “Try swapping out meat, dairy and eggs for plant alternatives – and try new things. It’s OK if you don’t like them the first time. Eventually, you’re going to find the plant choices that you do like.”

Mangano, a member of the university’s Center for Population Health, researches the nutritional value and health effects of different protein sources, as well as gut health and food additives. In addition to advanced nutrition courses, she teaches a popular course, Nutrition and Wellness, that counts as a science requirement for non-science majors.

Recently, she sat down to talk with us about the connections between food and a healthy planet.

Q: What is a sustainable diet?

A: It’s part of a food system that provides healthy food to all people in a way that protects the environment. 

There are so many food inequities in the United States and around the world. Making sure that all people have access to healthy, nutrient-dense foods is the foundation of a sustainable food system. That means a shift away from overconsumption of all foods and toward a more varied diet that includes more plants and fewer animal products.

Q: The United Nations’ Intergovernmental Panel on Climate Change recently released a report with a bleak warning about the environment, saying it’s “code red for humanity.” What were your main food-related takeaways from the report? 

A: Of the 4 billion tons of food produced globally each year, one-third of it is wasted. That blew my mind, especially since there are such high rates of food insecurity. 

In the United States, we have an obesity epidemic that is getting worse every year. Overeating is bad for our health, and through that overconsumption, we’re using all these fossil fuels in agribusiness to produce highly processed foods that we shouldn’t be eating in the first place.

The No. 1 thing we can do for ourselves and the planet is to reduce food waste overall. It’s really about getting back in tune with what our bodies need, and those hunger cues. 

In the dining hall, try putting a smaller amount of food on your plate. Eat it, and then consider, “Am I still hungry?” And if you’re still hungry, you can always go back for more. 

Q: The U.N. report says cows and rice are the two biggest agricultural sources of methane gas, one of the most damaging greenhouse gases. Is pork or chicken better for the environment than beef? What about eggs and dairy products?

A: All ruminant animals – cows, sheep and goats – release methane gas during digestion, so eating dairy products is only slightly better for the environment than eating beef, lamb and goat.

Rice production releases more methane gas than wheat or corn farming because of certain bacteria that grow in rice paddies when they’re flooded. But overall, industrial animal farming uses far more fossil fuels and other resources than plant agriculture, so eating plant-based foods is more sustainable than consuming beef, pork, chicken, fish, dairy and eggs. 

However, animal products provide a special combination of nutrients important to our overall health, so eating moderate amounts of sustainably produced meat, eggs and dairy from local farms is good for us. Pay attention to where your food comes from.

Q: If someone says, “I hate tofu and I’m never going to give up steak,” is there anything else they can do to cut down on greenhouse gas emissions? 

A: I ask my students to self-evaluate their food intake for a week. If someone finds that they’re eating meat at every meal – a sausage, egg and cheese sandwich for breakfast, a deli meat sandwich for lunch and then a big piece of meat for dinner – they can try to remove meat from one or two meals a day and replace it with plant protein.

Soy is the only plant we know of that’s a complete protein comparable to meat, so tofu and tempeh are good protein sources. Other beans and legumes combined with whole grains, nuts and nut butters, some veggie burgers and even mushrooms are good choices, too. 

Plant proteins provide so many vitamins and minerals, antioxidants, fiber and healthy oils that aren’t typically in animal protein. By swapping out animal protein for plant protein once or twice a day, you’re really bumping up the nutritive value of your diet and you have less of a carbon footprint. It’s a win-win.

Q: What about athletes, who may have different protein needs than the general population?

A: We now have research showing that younger adults only need 20 grams of protein in one meal or snack to stimulate new muscle growth and bone tissue. That’s about 3 ounces of meat, fish or poultry, or a veggie burger with a slice of cheese (or vegan cheese) at each meal. This is a good starting point, and then, depending on the athlete’s size and activity level, they can increase the protein in their meals as needed. If you over-consume protein, you will just turn it into fat tissue.

Q: What about some of the new meat substitutes, like Impossible Burgers and Beyond Burgers?

A: Say somebody has a portion-controlled, 4-ounce steak and a plate full of fruits and vegetables: I’d much rather see that than something that’s highly processed and loaded with salt or synthetic food additives. 

Many meat substitutes currently on the market are highly processed. Research in my lab and across the country suggests that processed foods and some food additives increase inflammation in the gut, which leads to chronic disease development, such as diabetes and cardiovascular disease. 

I’m an omnivore: I eat a mixture of plant protein and sustainably raised meat, but I try to eat food that’s as minimally processed as possible.

Q: What are some other tips for healthy, sustainable eating?

A: Take advantage of the unique, diverse environment in Lowell. If you can afford to eat out, it’s a neat opportunity to expand your cultural awareness and try more plant-based foods. Although plant proteins are not traditionally a staple in the westernized diet, they are a staple throughout the rest of the world.

There’s a big push in university dining for more vegetarian options and more locally sourced food. If you’re cooking for yourself, Lowell has a year-round farmer’s market at Mill No. 5 every Sunday and an outdoor farmer’s market downtown on Fridays from July through October. 

Buying locally grown fruits and veggies cuts down on fossil fuels used to transport food long distances, and you’re also getting more nutrients for your buck because exposure to air, heat and sunlight breaks down important vitamins. For example, you’re getting 80% more Vitamin C out of the greens in your backyard or from the farm down the street than if you bought them in the grocery store.

Finally, remember that sustainable food systems are those that provide nutritious food for all people. Support Our Students (SOS) is a nonprofit started by UML students that allows you to donate a meal from your meal plan to someone in need.