Debunking the Myth: Does freezing food reduce the calories?

Over 80% of households in the United States use a freezer to store food, yet a popular myth persists that freezing can somehow reduce a food's calorie content. In reality, the answer to the question "Does freezing food reduce the calories?" is a definitive no, as the cold storage process preserves energy, not removes it.

Quick Summary

Freezing food does not reduce its calorie count, as this process does not alter the energy content of macronutrients like protein, fat, and carbohydrates. The myth likely stems from a misunderstanding of how freezing affects food and its digestion.

Key Points

• Calories are not reduced: Freezing is a preservation method that stops microbial growth; it does not break down the macronutrients (carbohydrates, proteins, and fats) that contain calories.

• Nutrient retention is excellent: Freezing food, especially fresh produce harvested at peak ripeness, effectively locks in most vitamins and minerals, often preserving them better than prolonged refrigeration.

• Macronutrients remain stable: The freezing process does not alter the protein, fat, or carbohydrate content of food.

• The 'resistant starch' nuance is minor: While freezing and reheating starches can create resistant starch, the calorie-reduction effect is minimal and not a reliable diet strategy.

• Proper techniques are key: Using airtight containers, cooling food before freezing, and using the right cooking methods (like steaming) help preserve both quality and nutrients.

• Fresh vs. frozen: Frozen food can be a highly nutritious, convenient, and cost-effective alternative to fresh food, especially when fresh produce has traveled long distances or is out of season.

The Science of Freezing: How it Affects Calories and Nutrients

Freezing is a preservation method that works by lowering the temperature of food to inhibit the growth of microorganisms and slow down enzymatic reactions that cause spoilage. The core energy components of food—carbohydrates, proteins, and fats—are known as macronutrients. Freezing does not break down these macronutrients, which means the calorie count of a food item remains the same before and after freezing.

For example, a chicken breast with 165 calories per 100 grams will still have approximately 165 calories after being frozen and thawed, assuming no other ingredients or cooking methods are involved. The same principle applies to vegetables, fruits, and prepared meals. The total energy available from the food is locked in place by the low temperature, not destroyed.

The Myth of Reduced Calories in Frozen Food

One potential source of this misconception is a popular diet hack involving starches like rice. When starchy foods are cooked, frozen, and then reheated, some of the starches convert into a form called resistant starch. This type of starch is not fully digested by the body and, therefore, contributes fewer calories. However, the effect is often minor and does not equate to a significant calorie reduction, especially when considering a full diet. It's a subtle biochemical change, not a magical calorie-burning effect of the freezer itself.

Freezing's True Impact: Nutrient Retention

Instead of removing calories, freezing excels at locking in nutrients. In many cases, commercially frozen produce is more nutritious than its fresh counterparts that have been sitting in transit or on a store shelf for days.

• Peak Ripeness: Fruits and vegetables are often harvested at their peak ripeness before being quickly flash-frozen. This timing is crucial, as produce is most nutrient-dense at its peak.
• Preservation: Freezing halts the natural process of nutrient degradation that occurs over time in fresh food. This is particularly beneficial for water-soluble vitamins like Vitamin C and B vitamins, which are sensitive to heat, light, and oxidation.

While some nutrients might be lost during the blanching process—a quick dip in boiling water used for some vegetables before freezing—the overall nutrient retention of frozen produce is still impressive when compared to fresh food that has been stored for a week or more.

Macronutrients and the Freezing Process

The freezing process has minimal impact on the fundamental building blocks of food:

• Proteins: The structure of proteins remains stable at low temperatures, so the protein content of meat, poultry, and fish is not affected by freezing.
• Fats: Fats can become rancid over prolonged storage if exposed to air, but freezing doesn't inherently change the fat content. Proper packaging can prevent this.
• Carbohydrates: While the texture of starchy foods might change slightly, the carbohydrate content itself is preserved during freezing.

How to Freeze Food Properly to Maximize Nutrition

To get the most nutritional benefit from your frozen food, proper technique is key. Here are some best practices:

• Choose the Right Containers: Use airtight, freezer-safe containers or vacuum-sealed bags to prevent freezer burn, which occurs when air causes dehydration and quality loss.
• Cool Before Freezing: Allow hot foods to cool completely before placing them in the freezer to maintain their quality and prevent raising the overall temperature of your freezer.
• Freeze in Portions: Divide food into meal-sized portions before freezing. This allows for faster freezing and more efficient thawing, which reduces the chance of bacterial growth.
• Label and Date: Always label your packages with the contents and date to ensure you use items within their optimal storage time for best quality.
• Cook From Frozen: The way you cook frozen food can impact nutrient retention. Steaming or microwaving vegetables, for instance, is often better for preserving water-soluble vitamins than boiling them.

Fresh vs. Frozen Food: A Comparative Look

Factor	Fresh Food	Frozen Food
Nutrient Retention	Peak at harvest, degrades over time and transit.	Locked in at peak ripeness; retains most nutrients for months.
Shelf Life	Short, typically 3-7 days before nutrient loss accelerates and spoilage begins.	Long, typically 6-12 months with minimal nutrient loss when stored correctly.
Availability	Seasonal; availability varies throughout the year.	Year-round access to a wide variety of produce.
Convenience	Requires preparation like washing and chopping.	Pre-cut and washed, saving time on meal prep.
Cost	Can be more expensive, especially out-of-season.	Often more affordable and reduces food waste.

Conclusion

In conclusion, the idea that freezing food reduces its calories is a myth. The freezing process is a highly effective method of preservation that locks in the energy content and nutritional value of food for an extended period. Rather than focusing on a non-existent calorie reduction, consumers should embrace freezing for its proven ability to preserve nutrients, reduce food waste, and provide convenient, affordable access to healthy ingredients year-round. For the most nutritionally robust results, remember to use proper freezing techniques and cook your frozen ingredients carefully to maximize their retained vitamins and minerals.

References

• Food Safety and Inspection Service, USDA. Freezing and Food Safety. https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/freezing-and-food-safety
• Gourmet Meals AU. The Science Behind Frozen Meals: How Freezing Preserves Nutrition. https://gourmetmeals.com.au/blog-view/the-science-behind-frozen-meals-how-freezing-272
• PAK'nSAVE. Fresh vs frozen vegetables. https://www.paknsave.co.nz/money-saving-tips/fresh-vs-frozen-vegetables

Frequently Asked Questions

Can I refreeze food that has thawed?

You can safely refreeze thawed food if it has been kept cold and not left at room temperature for more than two hours. However, the quality, including taste and texture, may degrade each time it is thawed and refrozen.

Is freezing good for preserving vitamins?

Yes, freezing is an excellent way to preserve vitamins. For most fruits and vegetables, freezing locks in vitamins at their peak, and research shows that frozen options often have higher vitamin content than fresh produce stored for several days.

What is the best way to cook frozen vegetables to retain nutrients?

To retain the most nutrients, particularly water-soluble vitamins like vitamin C, you should cook frozen vegetables with minimal water and for a short time. Steaming and microwaving are generally superior to boiling.

Does freezing meat or fish affect its nutritional value?

No, freezing meat and fish does not destroy their nutritional value. The protein and fat content remain stable during freezer storage. Any minor changes in water-soluble vitamins are negligible when proper freezing techniques are used.

How does freezing prevent food from spoiling?

Freezing preserves food by lowering its temperature below the freezing point, which halts the activity of bacteria and other microorganisms that cause spoilage. It also slows down the chemical reactions that lead to food degradation.

Can freezing affect the texture of food?

Yes, freezing can affect the texture of some foods, especially those with high water content like delicate fruits, vegetables, and creamy sauces. Large ice crystals can damage cell walls, leading to a mushy texture upon thawing.

Is freezer burn a safety issue or a quality issue?

Freezer burn is a quality issue, not a safety issue. It occurs when food is exposed to air, causing dehydration and a loss of flavor and texture. While the food is still safe to eat, its quality will be diminished.