A study published in the American Journal of Clinical Nutrition says that almost 1,000 calories of a person's intake come from highly-processed food purchased when grocery shopping.

The research group gathered data from 157,000 people from 2000 to 2012, and tracked what kinds of food they're putting in their bags. The U.S. Department of Agriculture classifies processed food as "any edible that's not a raw agricultural commodity." 

They classified food into four groups. Minimally-processed food include fruits, vegetables, eggs and raw meat, and there are groups that compose of basic and moderately processed items lke sugar, oil and items with additives. 

The last group, which comprises about 61% of what people buy include food items that are mixed with chemicals and other foreign and unrecognizable substances. About 1.2 million products displayed on grocery shelves belong to this category. 

The study used software that reads the nutritional content found in each food item bought by the participants in the store. 

"It's important for us to recognize that a processed food is not just Coca-Cola and Twinkies-it's a wide array of products," says University of North Carolina's research assistant professor, Jennifer Poti, an author of the study. 

Sodas and energy drinks were found to contain the highest level of saturated fat, sugar and salt, which negatively affects consumers' health. Excessive intake of such products may lead to diseases like diabetes and obesity.

Healthline listed other processed food that will pose health risks if taken in excessive amounts. These include granola bars, bacon, instant ramen, margarine, flavored nuts, dried fruits, fruit candies, ketchup and frozen microwavable take-outs.

However, Poti also recognizes that, "Food processing is important for food security and nutrition security of Americans." Further, grocery shopping doesn't necessarily reflect dietary intake.

Researchers then suggest people buy "food that required cooking or preparation," like farm eggs, which contain 20% less calories than ready-to-serve food.