Why Do You Feel Cold When You Lose Weight?

If you've been shedding pounds lately, you may notice a lower tolerance for cold and a need for an extra layer or two. As it turns out, feeling cold when losing weight is totally normal. "Fat is really like the body's natural blanket. It's a natural layer of warmth and protection in our body," says Sylvia Gonsahn-Bollie, MD, the founder of EmbraceYOU Weight and Wellness. "So as we lose our fat stores, we do lose some of that thermodynamic energy —some of the heat that comes along with the fat."

Gradual weight loss and realistic body composition goals can help protect you from feeling chilly as you drop pounds. If you're feeling cold since losing weight, Dr. Gonsahn-Bollie suggests starting with the basics. "Make sure you get your labs checked so a doctor can see and make sure there are no secondary causes. Tell them you’re feeling cold, and get some bloodwork done."

Why You Feel Cold After Losing Weight

Feeling cold after weight loss is a common phenomenon with several causes. As fat loss occurs, so do other changes in your body.

"People forget that fat is actually a good thing, Gonsahn-Bollie says. "Fat is a vital organ in the body, especially when we think about heat generation."

Less Insulation From Body Fat

Low body fat levels may help you look and feel lean, but you need some essential fat for basic function.

A healthy percentage of body fat is 25 to 31 percent for people assigned female at birth and 18 to 24 percent for people assigned male at birth, but age and athletic status are also factors, according to Baylor College of Medicine. What counts as a healthy body fat percentage varies from person to person.

This essential fat pads your internal organs, absorbs vitamins, and acts as insulation. Cleveland Clinic says fat cells also release energy when they sense cold temperatures, which helps keep you warm.

When body fat drops too low, you lose insulation, making you more sensitive to temperature drops.

Nutrient Deficiencies

Another reason you feel cold might be a change in dietary nutrients. Weight loss and dieting typically involve eating less food to create a calorie deficit (taking in fewer calories than you burn). You may be unknowingly denying yourself essential nutrients such as iron, vitamin B12, and folate.

"It's important not to eliminate food groups," Gonsahn-Bollie says. "You do need the nutrients that come from different food sources. If you're following a plant-based eating plan, then you want to make sure you're getting enough iron."

Not getting enough iron can result in anemia, she says, a condition in which your body has trouble producing enough red blood cells. These carry oxygen to your internal organs and tissues.

If your coldness occurs along with the following symptoms, talk to your doctor about your diet and the possibility of doing blood tests to evaluate your nutritional status:

• Mood changes
• Fatigue
• Brittle nails
• Regular headaches

"This is your body trying to communicate something to you. So we need to listen and then do further evaluations,” says Gonsahn-Bollie.

Nutrient-dense foods can help prevent nutrient deficiencies. Foods high in iron include:

• Meat
• Eggs
• Leafy greens
• Iron-fortified foods like milk and cheese, according to Mayo Clinic

"If you're following a standard Western diet or eating a lot of ultra-processed foods without also eating nutrient-dense foods, you may be missing some nutrients," Gonsahn-Bollie says.

Metabolism Changes

A calorie deficit can lead to weight loss, but too much too soon can have negative consequences. Taking in too few calories to lose weight might cause cold intolerance, even if you haven't experienced significant drops in body fat or weight.

"It can also depend on how rapidly you lose weight. The body's hormones have to adjust to that,” Gonsahn-Bollie says. "It's possible to have fluctuations in your thyroid hormone, which is another big heat regulator in the body as well."

When your thyroid gland produces less thyroid hormone, you might feel cold. Sudden changes in your diet and calorie intake can slow your metabolism and negatively affect hormone production. Restricting calories too much can cause your body to break down muscle for energy, and, in turn, that reduction in muscle mass slows metabolism, according to Cleveland Clinic.

What to Do About Feeling Cold During Weight Loss

Feeling chilly might mean you reach for a sweater or jacket to warm up. Besides the obvious solution of wearing more clothes, there are other steps to address this side effect.

If the chill in your bones is due to nutrient deficiencies, practice adding more whole foods to your diet. "Really look at the quality of the foods you're eating," Gonsahn-Bollie says. "It might be helpful to add a multivitamin to your routine." If you or your doctor suspect you need a dietary supplement, choose a multivitamin that fulfills your nutrient needs.

Gonsahn-Bollie also suggests paying attention to when you feel cold. "Sometimes people can feel cold immediately after exercising outdoors when it's cold outside. That's because of your sweat glands opening up. Make sure you have something warm to drink and use warm compresses."