When you start dieting, you may quickly notice physical changes in your body. Frew explained that you'll feel the cold more, get headaches, feel low energy, and will experience intense hunger and cravings for food. You'll find it hard to concentrate and can feel dizzy or spaced out. "You can also lose muscle mass, particularly if you're crash dieting," Frew added, and losing muscle mass can actually slow down your metabolism.
Previte added that dieting can also cause physical anxiety symptoms. If you're stressed about your food choices, or go somewhere that doesn't have your "diet-approved foods," anxiety can cause tightness in your chest, a racing heart rate, and the fear can bring you to tears.
"Continuing to follow the food rules may feel like the 'right' thing to do to curb the physical responses in the body, but there will always be an event or time that you won't be able to abide by the rules," Previte said.
"Worrying about your weight is a form of weight stigma, which studies show causes increased levels of the stress hormone cortisol and puts people at risk of health problems like heart disease, diabetes, and early mortality," explained Harrison. In fact, a 2017 study found that weight stigma is a greater risk to people's health than what they eat!
Harrison explained that restrictive eating can also cause increased cortisol levels, and chronically elevated cortisol levels can lead to reduced immunity and an increased risk of infection.