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Diet Habits Wrecking Your Immune System, Say Dietitians

If you want to fight off infection and disease, it's time to ditch these eating habits now.
FACT CHECKED BY Olivia Tarantino

With fall fast approaching, cold and flu season isn't far behind. For many people who want to avoid getting sick, frequent hand washing and steering clear of crowds has already become a priority. However, there's one crucial step toward protecting your immune system that many people aren't taking: revamping your eating habits.

If you want to protect your wellbeing, read on to discover the eating habits that could be wrecking your immune health, according to experts. And if you want to keep your body healthy, check out The One Vitamin Doctors Are Urging Everyone to Take Right Now.

Eating too much sugar

blonde woman eating a cookie and reading
Shutterstock / Ollyy

Those sugary pumpkin lattes and Halloween cookies could be wreaking havoc on your immune health.

"Excess intake of sugar and simple carbohydrates can reduce immune cell function and weaken the immune system," explains Lindsey DeSoto RDN, LD, of Fit Healthy Momma.

If you want to give your immune system a leg up, This One Diet Can Protect Your Immune System, New Study Says.

Drinking alcohol

Black woman drinking red wine

If you want to keep your immune system working effectively, you may want to keep your alcohol consumption to a minimum.

"Excessive alcohol intake of over 14 drinks per week can suppress your immune system and can lead to more severe symptoms when you do get sick," explains DeSoto.

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Eating processed snack foods

person in blue button down eating from bag of chips

While processed snacks, like chips and cookies, may be convenient, they could be doing a number on your immune health.

"Highly processed foods contain high amounts of sodium, saturated fat (potentially even trans fat), and sugar. These components can lead to developing heart disease and kidney disease, leading to chronic inflammation and compromising your immune system," says Leonila Campos, MBA, RD, CEO and founder of Fueled by Leo, Inc.

Eating fast food

young woman eating chicken in fast food restaurant
Shutterstock / The_Molostock

If you want to keep your immune system working effectively, you may want to think twice before hitting the drive-thru.

"Fast foods are high in saturated fats and low in unsaturated fat. High saturated fat intake can prompt inflammation in the body, thus weakening immune function," explains registered dietitian nutritionist Hannah Byrne, MS, RDN.

Eating too much salt


Before you pick up that salt shaker, consider the risk that extra sodium could be posing for your immune health.

"Excessive sodium intake causes high blood pressure and fluid retention," says Byrne. "Fluid retention causes the kidney to then excrete excess sodium, which then can reduce the body's ability to fight infection."

Not eating enough calories

Displeased young woman doesn't want to eat her breakfast

While eating the wrong foods can have serious consequences for your immune health, eating an insufficient number of calories can have the same effect.

"People who purposely restrict their food intake or suffer from disordered eating behaviors or an eating disorder are more susceptible to harming their immune system," says Roxana Ehsani, MS, RD, CSSD, LDN, a national media spokesperson for the Academy of Nutrition and Dietetics. "When we don't nourish our bodies with enough nutrients each day, we aren't supporting a healthy and strong immune system."

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Sarah Crow
Sarah Crow is a senior editor at Eat This, Not That!, where she focuses on celebrity news and health coverage. Read more about Sarah