A common perception is that “healthy foods” are more expensive than less healthy foods. Researchers from the US Department of Agriculture Economic Research Service looked at three different ways to compare costs. One method was to look at the price per calorie, another to examine price per edible grams and the third, to look at the price per average portion size. They also looked at the price of meeting the Federal dietary recommendations for each food group.
Andrea Carlson and Elizabeth Frazao found that healthy foods were cheaper than less healthy foods, except for the price per calorie. Foods low in calories, like fruits and vegetables, appear to have a higher price when measured on a per calorie basis. When measured on the basis of edible weight or average portion size, grains, vegetables, fruit, and dairy foods are less expensive than most protein foods and foods high in saturated fat, added sugars, and/or sodium. USDA ERS: Are Healthy Foods Really More Expensive?
But what does this mean for your diet? If you consume the recommended amount of fruits and vegetables and other low calorie foods, you still need calories to meet your minimum daily intake requirements. So, if the “bad foods” are more expensive, that is a good reason to drop them from your diet? Well, yes if you want to save some money. But what if you are trying to lose weight? Earlier studies have suggested that reducing variety in non-nutrient dense, energy-dense food groups (think ice cream, potato chips, cookies, and candies) may result in lower overall energy intake and thus improve weight loss and weight management. The mechanism is thought to be ‘hedonics’, that the more boring the food is the less it is consumed.
In a clinical trial, Rena Wing and colleagues 200 adults were randomly assigned to either a lifestyle or lifestyle plus limited variety diet. Both groups received 48 group sessions over an 18-month period, covering cognitive behavioral intervention, a diet prescription, and a physical activity prescription.
The lifestyle + limited variety group was limited to 2 self-selected non-nutrient dense energy dense foods including baked goods, granola snack bars, high-fat crackers, frozen dairy-based deserts, frozen yogurt, ice cream, ice milk, cheese, candy, chips, salty snacks, and chocolate.
The results? Intake from this category was reduced, but overall energy was not and there was no difference in weight loss between the two groups. PubMed: Limiting Variety in non-nutrient-dense foods