If you find yourself yawning in the middle of meetings and reaching for an extra cup of cold brew to get you through the afternoon, your diet may be to blame. “Not enough calories and nutrients can lead to weakness [and] fatigue,” says Ilyse Schapiro, R.D., C.D.N., and co-author of Should I Scoop Out My Bagel? “You might find that you tire quickly,” adds Darla Klokeid, M.D., a One Medical physician in Seattle. “You might not have the tolerance for usual activities like going up stairs.”
Another sign that you need to slow down? “Tiring quickly with routine activities you’ve been doing like household tasks or workouts that are your baseline,” Klokeid says. And this applies regardless of your weight. “You might be a ‘normal weight’ but if you’re losing more than two pounds a week you can experience things like . . . feeling fatigued. If you feel dizzy, lightheaded, and weak all the time you know that you’re not getting enough calories,” she adds.
If your face looks gaunt or drawn, you may have lost too much weight, says Braverman. “When I work with patients for weight loss, I work with them to also add muscle. The majority of people when they lose weight too fast . . . they lose water, and meanwhile their body devours muscle,” he explains. “[That] can leave them with . . . gaunt face.”
A lower number on the scale doesn’t necessarily mean a leaned, toned body. A quick loss of muscle can be responsible for all-over flabbiness, says Braverman. In fact, the number on the scale doesn’t really matter. Thin and overweight people alike can be flabby if they lose weight too fast, he adds.
If you’ve lost too much weight, you may have also lost a lot of water weight, which can cause rapid hair loss, says Braverman. And it’s not just how much you’ve lost. What you’re eating—or not eating—can affect your locks, too. Hair is made of keratin, a protein. “Certain diets can cause hair loss such as diets without protein,” he adds. A deficiency of iron, zinc, niacin, and omega-3 and omega-6 fatty acids can also lead to a thinner head of hair.
If a throw blanket has become a permanent staple of your wardrobe, your metabolism may be to blame. It’s normal to lose some of your natural insulation—body fat—as you lose weight. But if you’re seriously dropping your calorie intake, your metabolism may be also compensating by slowing down, which can leave you feeling a perma-chill.
“You might notice that you are irritable, angry, or feel depressed,” says Klokeid. “Your brain especially needs the right building blocks to make neurotransmitters to keep your mood normal,” she explains. “Foods high in certain amino acids can stimulate the production of neurotransmitters, certain nutrients can help slow neural degeneration (good to keep all the neural function possible), and nutrients are also used to make neurotransmitters like amino acids.” When you’re not getting those nutrients, your brain isn’t functioning as well as it should. “Brain processing functions won’t be as effective,” Klokeid adds.