How Many Calories Are in a Fly? Nutrition Facts and Consumption

Determining Calorie Content of Flies

Flies are not commonly thought of as a food source, but they are in fact edible insects. With interest growing in entomophagy (consumption of insects as food), some people are curious about the calorie and nutritional content of flies.

There are over 120,000 identified species of fly. Calorie content varies between fly species based on size and other factors. But most flies provide minimal nutritional value to humans.

This article will examine the estimated calorie counts for various household and outdoor fly species. We’ll look at how fly calories compare to other insects and protein sources. Tips for safely capturing and preparing flies for human consumption will also be covered.

Calorie Counts of Common Fly Species

Here are approximate calorie amounts for some of the most prevalent fly varieties:

House Fly

The common house fly weighs about 2 to 4 mg on average. Estimates suggest each house fly contains approximately 0.1 calories.

Fruit Fly

A fruit fly weighs less than 1 mg typically. Each individual fruit fly contains negligible calories, providing 0.05 calories or less.

Blow Fly

These flies consume decaying organic material and lay eggs on carrion. Blow flies weigh 6 to 15 mg. You can expect roughly 0.2 to 0.5 calories per blow fly.

Horse Fly

Horse flies and deer flies are larger, often around 10 to 20 mg. About 0.3 to 0.6 calories come from each horse fly.

Bot Fly

Bot flies are parasites that feed on living mammals by laying eggs beneath the skin. They can reach sizes over 15 mg. Expect 0.5 calories or more per bot fly.

Flesh Fly

These flies deposit larvae on dead animals to consume decaying flesh. They weigh 10 to 18 mg typically, containing around 0.3 to 0.5 calories each.

Calorie Comparison of Edible Insects

Compared to other edible insects, flies contain very minimal calories and nutritional value:

Crickets

Crickets provide about 5 to 7 calories per cricket. A single fly provides less than 1/50 the calories of a cricket.

Mealworms

A mealworm contains approximately 4 to 5 calories. You would need to eat over 50 house flies to equal the calories in a single mealworm.

Grasshoppers

There are roughly 20 calories in one medium sized grasshopper. In contrast, 100 fruit flies only provide about 5 calories combined.

Silkworm Pupae

Silkworm pupae have an estimated 28 calories each. Even a larger horse fly only provides around 1/50 the calories of a single silkworm pupa.

Fly Calories Versus Other Foods

Here’s how fly calorie counts compare to some other foods:

Beef

There are about 50 calories in a gram of cooked ground beef. You would need to eat over 500 house flies to equal the calories in a single gram of beef.

Rice

A gram of cooked white rice provides around 35 calories. To match that, you would have to eat approximately 350 fruit flies.

Bread

One slice of white bread has about 70 to 80 calories. So you would need to eat around 800 house flies to get a comparable amount of calories.

Apple

There are roughly 50 calories in a medium apple. That’s the equivalent of 500 house flies worth of calories.

Nutritional Value of Flies

In addition to minimal calorie content, flies offer very little nutritional value:

Protein

Flies have trace amounts of protein. But the protein content is negligible compared to most other insects and animal products.

Fat

The fat content in flies is extremely low, providing minimal nutritional fat value.

Vitamins and Minerals

Flies contain only trace amounts of micronutrients like vitamins, minerals, and antioxidants.

Fiber

There is no fiber in flies. Other insects like crickets provide a significant amount of fiber.

Difficulties of Sourcing Fly Nutrition

Trying to gather meaningful nutrition from flies poses some significant challenges:

Labor Intensive Harvesting

It's extremely labor intensive to capture enough flies to make a nutritious meal or food product. Each fly only provides a fraction of a calorie.

Food Safety Risks

Eating flies poses food safety issues since flies spread pathogens like bacteria, viruses, and parasites.

Unpleasant Taste

Flies do not have a pleasant taste or appeal as a food item for most humans.

Difficult Processing and Cooking

The tiny size of flies makes them difficult to process and prepare into an appetizing dish.

Lack of Acceptance

There is low consumer acceptance and appeal for flies as a nutritional food source in Western cultures currently.

Capturing Wild Flies for Consumption

Harvesting wild flies for human consumption comes with hazards. But here are some tips if you wish to capture flies safely:

Flypaper

Sticky flypaper will catch flies without contaminating them with toxic pesticides. But removing flies from the paper is challenging.

Jar Traps

Leaving out jars filled with fruit or rotting meat will attract flies. Cover the jar opening with plastic wrap and secure it with a rubber band to trap flies.

Bug Net

Capture flies outdoors by swinging a bug net quickly to enclose flies inside. Then transfer to a sealed container.

Vacuum Nozzle

Use a vacuum cleaner nozzle and hose to suck up flies. Place pantyhose over the nozzle first so flies don't get pulled into the vacuum.

Preparing and Cooking Flies for Consumption

If you plan to eat flies, here are some preparation and cooking methods:

Washing Flies

Rinse flies in a colander under running water to remove dirt and potential contaminants. Pat dry with a paper towel.

Blanching

Blanch flies in boiling water briefly to sterilize them and make their wings and legs easier to remove.

De-winging

It's recommended to remove wings and legs from flies before eating them for safety and digestibility.

Roasting

Roast flies in the oven at 400°F until crispy to enhance flavor and destroy pathogens.

Frying

Pan fry flies in a small amount of oil briefly. Add salt and other seasonings to improve the taste.

Powdering

Dry flies completely and then process them into a fine powder with a blender, food processor, or mortar and pestle.

Is Eating Flies Recommended?

Despite their edibility, flies are not an optimal food choice for humans from a health and nutrition perspective for several reasons:

Low in Nutrients

The calories and nutrients available from flies are negligible compared to most other edible insects and animal products.

Difficult to Source

It takes an impractical amount of labor to harvest flies in meaningful quantities for food purposes.

Contamination Risks

Flies can transmit dangerous bacteria, viruses, and parasites to people who eat undercooked flies.

Unpalatable Taste

Flies generally do not have an appealing flavor or texture according to most human preferences.

Lack of Acceptance

There is low appeal and acceptance for flies as food right now in many societies.

With their low calorie content, lack of other nutrients, and unappealing taste, flies are unlikely to gain traction as a viable food source.

Trying Flies for Survival Situations

While not ideal for regular nourishment, flies could provide sustenance in certain survival situations when no other food sources are available. In an emergency scenario, flies offer:

Source of Calories

Though minimal, flies do provide some calories to sustain energy in desperate times when facing starvation.

Potential Trace Nutrients

Eating flies might supply tiny amounts of protein, fat, vitamins and minerals to temporarily stave off nutritional deficiencies.

Abundant Supply

Flies are often plentiful and easy to capture, providing an accessible source of potential food year-round.

Motivation to Keep Trying

The process of catching and eating flies can provide motivation and a sense of purpose to boost morale for survival.

The challenges of safely sourcing and preparing flies to avoid illness may outweigh potential benefits. But in dire circumstances, flies could temporarily help sustain life.

Summary

Most fly species provide only trace amounts of calories and nutrients. You would have to eat hundreds of flies to equal the calories and protein in just one insect like a cricket or grasshopper.

Trying to harvest meaningful nutrition from flies poses many challenges. The labor involved, safety risks, and unappealing flavor make flies a very impractical food choice.

While edible as part of entomophagy, flies realistically provide minimal nutritional incentive for human consumption beyond survival situations with no other food available.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.