13 Things Fast Food Does to Your Body

Processed carbs in fast food translate to weight gain and obesity if you indulge too often.

Packs on the Pounds

Fast food is convenient and cheap, but you pay a bigger price in the long run. Those burgers, fries, and shakes usually have more fat, calories, and highly processed carbs than your body needs in one meal. This can quickly lead to weight gain and obesity if you eat it often.

Bacon cheeseburgers often contain more than the suggested daily amount of sodium, which can raise blood pressure and damage blood vessels.

Harms Your Heart

Sodium makes fast food taste better and keeps it from spoiling. But just one bacon cheeseburger can contain your recommended daily value for sodium. That's the amount of a nutrient experts suggest getting every day. Too much sodium raises your blood pressure and damages your blood vessels. It also raises your risk for heart failure, heart attack, and stroke.

White breads are high in processed carbs that break down quickly into sugar, causing your body to pump out insulin which stresses your pancreas.

Spikes Blood Sugar

Bagels, buns, and breaded foods are high in processed carbs your body breaks down into sugar. As blood sugar levels rise, your body pumps out insulin to level things out. Over time, these constant sugar spikes can wear out your pancreas (the organ that makes insulin). This keeps blood sugar levels high, triggering type 2 diabetes.

High-sodium, low-fiber fast food can cause bloating and other digestive problems.

Opens the Door to Digestive Issues

Fast food may taste good, but you may not feel well once it hits your system. High-sodium foods (fries, anyone?) can temporarily trigger bloat. Couple that with low amounts of dietary fiber, and your digestive tract gets backed up. This can lead to constipation that puts you at risk for hemorrhoids, hernias, and diverticulitis.

Fast food lacks vitamins, minerals, and nutrients that are critical for your brain health and mood.

Affects Your Mood

What you eat and drink can impact how you feel mentally and physically. Fast food lacks the vitamins, minerals, and other nutrients your body needs to boost your mood. Research suggests fast and processed foods you buy at the store may be linked to a higher risk of depression.

Processed carbs in fast food give you a blood sugar spike followed by a crash.

Makes You Tired

When a bunch of processed carbs hit your system, your blood sugar rises quickly, then drops just as fast. This can make you feel tired. If you grab a sugary coffee drink to wake up, the cycle starts all over again.

Fast food contains chemicals that may negatively impact fertility.

Could Impact Your Fertility

Phthalates, synthetic chemicals that dissolve materials and make plastics durable, are in everything from toys to fast food. Recent studies have linked phthalates with fertility issues and higher risks of learning and behavioral disorders in children.

Fatty fast food may trigger diarrhea.

Changes Your Bathroom Habits

Because it's highly processed, fast food -- especially the kind that's fried or creamy -- can be hard to digest. If your body can't break it down, it lands in your colon and turns into fatty acids that spark diarrhea.

Carbs in fast food lead to acid formation, which erodes your teeth.

Invites Dental Disease

The high levels of carbs and sugar in fast food, including sodas, raises the amount of acids in your mouth. These wear down the enamel on your teeth and boosts your risk of cavities, tooth decay, and gum disease.

Fast food contributes to obesity which is bad for your hips, knees, and other joints.

Wears Out Your Bones and Joints

Excess weight and obesity caused by fast food puts extra pressure on your joints, especially your hips and knees. This makes you more likely to get fractures in the bones around your joints.

Fatty fast food contributes to excess weight and inflammation, which may aggravate asthma.

Raises Your Risk for Respiratory Issues

One fried chicken dinner won't affect the way you breathe. But too much fast food can lead to extra weight that increases your risk of asthma, especially in women. More research is needed to know exactly why, but early studies show that fat tissue leads to inflammation that may affect your lungs.

Sugar, salt, and saturated fat in fast food contributes to skin aging.

Causes Skin Outbreaks

Fast food is full of ingredients that don't play well with your skin. Sugar can lower collagen levels and lead to signs of early aging, like wrinkles. Salt drains moisture from your skin, but it helps your body keep the water that causes bags under your eyes. High amounts of saturated fats trigger hormones that play a role in acne.

Fast food is high in saturated and trans fats, which increase plaque formation in the brain that causes dementia.

Affects Your Memory

Experts think saturated and trans fats tell your body to make plaques in the brain. These cause dementia and raise your risk of Alzheimer's disease three times more than those who don't eat fast food.



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  • Cleveland Clinic: "Here's How Fast Food Can Affect Your Body," "Want Healthy Skin? Limit These 5 Types of Foods."
  • Harvard T.H. Chan School of Public Health: "Carbohydrates and Blood Sugar."
  • CDC: "Phthalates Factsheet."
  • Environmental Health News: "Fast food burgers, fries, and pizza may leave you full of phthalates."
  • Harvard Health Publishing: "Is something in your diet causing diarrhea?"
  • University of Rochester Medical Center: "The Best and Worst Foods for Your Teeth."
  • Oral Health Foundation: "Diet and my teeth."
  • American Academy of Orthpaedic Surgeons: "The Impact of Obesity on Bone and Joint Health."
  • American Lung Association: "The Link between Asthma and Weight."
  • Physicians Committee for Responsible Medicine: "Baby Boom + Fast Food = Dementia Boom."
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