1. Potato Chips
Crunchy, salty, and endlessly snackable, potato chips are a classic ultra-processed food that can quietly sabotage your metabolism. They’re typically fried in unhealthy oils and packed with sodium, making them highly inflammatory. “Processed snacks like potato chips can slow down metabolism because they are high in calories, unhealthy fats, and sodium,” explains Dr. Zeeshan Afzal. “These snacks can cause inflammation because the high levels of unhealthy fats and sodium can contribute to chronic inflammation in the body.” Over time, this inflammatory state can encourage visceral fat storage, especially around the midsection.
2. Cookies
Cookies may feel harmless in small doses, but they’re often loaded with refined sugar and fats that add up quickly. Jesse Feder, a dietitian, warns that cookies present many of the same risks as pastries and cakes, noting they are “typically high in fats, sugars, and calories.” Because they’re easy to overconsume, cookies can push you well past your daily calorie needs without making you feel full. “The high amount of calories in these products can lead to unwanted fat gain over time,” Feder says—particularly visceral fat when eaten regularly.
3. Sugary Breakfast Cereals
Many breakfast cereals, especially those marketed to kids, are ultra-processed and sugar-heavy despite their “healthy” branding. According to experts, these cereals spike blood sugar and offer little in the way of fiber or protein to keep you satisfied. “Many breakfast cereals targeted at children are high in sugar and lack nutritional value,” nutritionist Krutika Nanavati notes. “Consuming these regularly can lead to weight gain and increased risk of chronic diseases.” Starting your day with a sugar rush can also set the tone for cravings and overeating later on.
4. Muffins
They may sound wholesome, but muffins are often just cake in disguise. Bakery-style or boxed muffins can be surprisingly calorie-dense, making them a risky regular snack. “You may call them muffins, but my brain says, cake,” says Lisa Andrews, MEd, RD, LD. “Whether they're from a bakery or a box, traditional muffins are high in calories and fat, which could lead to belly fat over time. Some of them contain over 350 calories per muffin.”
5. Chocolate-Dipped Granola Bars
Marketed as a “healthy” option, chocolate-dipped granola bars often fall short of that promise. They’re usually packed with added sugars and saturated fats while lacking meaningful nutrients. “While these may be marketed as a healthy snack, they are basically candy bars in disguise,” Andrews shares. “Most are high in sugar and saturated fat with little nutrition inside. They may cause weight gain in your belly if they become a staple in your pantry.”
The Bottom Line
After 40, cutting back on ultra-processed snacks isn’t about restriction—it’s about being strategic. Foods high in refined sugar, unhealthy fats, and sodium promote inflammation and make it easier for visceral fat to accumulate. Swapping these snacks for whole-food options like fruit, nuts, yogurt, or protein-rich bites can support a healthier metabolism, reduce belly fat, and help you feel more energized long-term.