I'm a doctor who studies longevity. Here are 8 things I always put in my Trader Joe's cart — and 4 I never buy.

As a doctor studying longevity, my usual Trader Joe's cart covers fiber, omega-3s, fermented foods, and healthy fats. Ingrid Yang As a physician studying longevity, I'm mindful when filling up my cart at Trader Joe's. I buy a lot of fresh and frozen produce, plus fiber-packed legumes and lentils. Premade frozen entrées have too much sodium for me, and I prefer local produce over salad kits. I'm a board-certified internal medicine physician who studies longevity , so I'm used to people asking me how to live longer. Often, they expect a prescription, a supplement stack, or some expensive scan. However, the most honest answer I can give them is in a grocery cart. Mine gets filled at Trader Joe's most weeks, and I'm not chasing superfoods or miracle ingredients. Rather, I'm looking for foods that deliver fiber, healthy fats , and protein without the sodium and added sugar that can easily accumulate in a modern diet. Here are a few things that always go in my cart, plus what I intentionally leave out. Spoiler alert: One of my must-buy items isn't even food. Beans and lentils are the backbone of my week. Ingrid Yang Legumes show up in the daily diet of nearly every long-lived population I've studied. They are fiber-packed and protein-dense — two longevity heavy hitters. Fiber is the most under-consumed nutrient in the American diet, and legumes deliver it alongside plant protein. Fiber can help feed the gut microbiome and support steadier blood sugar after meals. I regularly buy legumes like beans and lentils on my trips to Trader Joe's. Typically, I cook a pot of lentils on Sunday and spend the week folding them into eggs, salads, and grain bowls. Extra-virgin olive oil and fresh avocados cover my "healthy fats." Ingrid Yang Olive oil is considered a "healthy fat" for a lot of reasons. For one, it has polyphenols, which contain antioxidant properties that can help protect against the development and progression of a range of health conditions. Avocados are also considered a "healthy fat" and a great source of potassium, which can help counterbalance dietary sodium and support healthy blood pressure. They contain more fiber than you might expect, too, at around 10 grams for a medium avocado. I like using olive oil for cooking and as a finishing drizzle after plating my meals. The avocado goes on eggs or gets cubed into bean-based bowls. Frozen Alaskan wild-sockeye fillets are my protein workhorse. Ingrid Yang My go-to frozen wild sockeye salmon fillets have one ingredient on the label: fish. Because this salmon is not smoked, marinated, or cured, they're also much lower in sodium. The plain fillet has a fraction of the sodium as the smoked salmon in the next case over, along with EPA and DHA omega-3s, which can help support cardiovascular and brain health. For an easy dinner, I roast this salmon at 400 degrees Fahrenheit for 12 minutes and serve it over sautéed greens. Raw, unsalted nuts are always in my pantry. Ingrid Yang Walnuts and almonds pack a protein punch, and the unsalted part is non-negotiable. Eating salted nuts as a frequent snack can quickly raise one's sodium intake. Over time, chronic excess sodium intake can contribute to hypertension (high blood pressure) — the leading modifiable risk factor for stroke . When I shop at Trader Joe's, I grab unsalted walnuts, almonds, or whatever I'm craving, then pair a serving of nuts with fruit as my standing afternoon snack. Also, chopped walnuts are delicious sprinkled over roasted vegetables. Plain Greek yogurt is a staple. Ingrid Yang Fermented dairy products, like Trader Joe's Greek yogurt, contain live active cultures (which can help support gut health ) and provide decent amounts of protein. Each ¾ -cup serving of Trader Joe's plain, whole-milk Greek yogurt contains 17 grams of protein. Whenever I purchase Greek yogurt , I go for plain varieties. This is important because many flavored yogurts contain way more added sugar. For comparison, Trader Joe's 5.3-ounce plain, whole-milk Greek yogurt contains 5 grams of added sugar. With 9 grams of added sugar, the apricot-mango variety contains almost twice as much. Luckily, it's easy to sweeten up plain yogurt with berries. I also like to add nuts for a crunch. When it comes to cooking, plain Greek yogurt is a great swap for sour cream in almost any dish. I keep fruit around in almost every form. Ingrid Yang I often buy fresh fruit, but Trader Joe's frozen strawberries and wild blueberries are anchors in my household. I like that frozen fruit is typically picked and preserved at peak ripeness, costs less than fresh, and is immune to the slow tragedy that overtakes whatever is decomposing in the back of the produce drawer. Berries go on yogurt and oatmeal, and whatever is in season gets paired with nuts. Chia seeds go into almost everything. Ingrid Yang A single ounce of chia seeds contains about 10 grams of fiber, a bit of protein, and plant-based ALA omega-3s (which can promote heart health). The seeds absorb liquid and turn gelatinous, which can help slow digestion and keep meals satisfying longer. Blend them into smoothies, add to salad, or soak them overnight for a pudding. A bag from Trader Joe's costs a few dollars and lasts months in my pantry. Greeting cards might be the most important thing in my cart. Ingrid Yang Longevity isn't only about what you eat. Social connection has been widely linked to longevity , and it can be as powerful as diet and other lifestyle factors people obsess over — and I believe a handwritten card is connection you can hold. Fortunately, Trader Joe's has a great selection of blank greeting cards for just 99 cents each. These cards make it even easier to stay in touch with people. I buy a stack, keep them in a drawer, and send one the moment someone crosses my mind. Whether saying congratulations, expressing gratitude, or letting someone know I'm thinking of them, putting pen to paper is meaningful to me, and to the recipient. On the other hand, I don't buy frozen entrées here or at any grocery store. Ingrid Yang I'm sure many frozen premade meals are convenient and taste just fine — there's a reason they're so popular, especially at Trader Joe's— but my issue with most of them is the sodium content. Many of these premade dishes contain several hundred milligrams of sodium per serving. I've seen some that contain close to 1,000 milligrams of sodium per serving — that's almost half the recommended daily limit for an average adult in a single meal. And, as I've mentioned, chronic excess sodium intake can raise blood pressure, increasing cardiovascular risk. Instead, when I need a quick meal, I cook up frozen vegetables, frozen grains, and a can of beans or a sockeye fillet. Either option only takes me about 10 minutes to prep. I don't purchase bagged leafy greens and salad kits, either. Ingrid Yang As convenient as bagged salad kits and pre-washed greens seem, they're not worth it for me. Tender greens start losing water-soluble vitamins like folate and vitamin C the moment they're cut and stored. And by the time bagged greens reach my cart, they may already be several days — or more — from harvest. Instead, I get my greens from my local CSA produce box or farmers market, where they're often harvested much closer to when I buy them. They keep more of their nutrients and taste fresher, which means I'm more likely to actually eat them. Sweetened dried fruit doesn't make it into my basket. Ingrid Yang In my opinion, sweetened dried fruit sounds healthy but is actually more like candy. Whole fruit delivers its sugar packaged with fiber and water, which changes how the body handles it compared to juice or dried versions. Drying concentrates sugar while stripping out the water that makes whole fruit filling. Plus, a lot of dried fruits are coated in sweeteners, which pushes this snack further up the glycemic index. I'm choosing frozen or fresh fruit over the sweetened, dried versions every time. For me, cured and processed meats stay on the shelf. Ingrid Yang The World Health Organization classifies processed meat as a Group 1 carcinogen, a category it uses when there is "convincing evidence that the agent causes cancer." To each their own, but that alone is enough for me to just stay away from this section of the grocery store altogether. Curious what's in other shoppers' carts? Keep reading our Trader Joe's diaries . Read the original article on Business Insider