Little white lies aren’t so bad when you’ve been gifted a not-so-great sweater. But when it comes to your diet, honesty is the best policy. The small food fibs you tell yourself (“I need to eat this macaroni and cheese to get through the pandemic”) can sabotage your health goals. Here are a few common examples of diet self-deceptions, and how to combat them.

• “I’m not losing weight because my metabolism is slow.” 

Your resting metabolic rate—the rate you burn calories during inactivity—could be to blame for those stubborn pounds. But, chances are you’re just eating more than you think and not exercising enough. With any weight gain, behavior is often a big component.

Still, why not test the theory? Some physicians’ offices (and some upscale gyms) offer an indirect calorimeter to check your metabolic rate. This simple test, which costs $50-$100, measures the level of oxygen and carbon dioxide going in and out of your lungs and determines your caloric output.

An abnormal (slow) result could signal a thyroid problem or a sleep disorder. However, it’s more likely that in order to budge the scale you’ll need to track calories with a food diary, get a good night’s sleep and exercise more to build muscle—the engine that drives metabolism. Doing all of those things may raise your metabolic rate by 5 to 10 percent, or an extra 100 calories per day.

• “I can just eyeball my portion sizes to gauge calories.”

“Most of us aren’t good at perceiving how much we eat,” said Sandria Godwin, RD. In her research, when subjects judged portion sizes just by looking at them, they underestimated amounts by an average of 23 percent.

If you’re serious about controlling portions, don’t guesstimate. Weigh meat with a food scale (aim for 3 ounces per meal) and measure everything else with teaspoons, tablespoons and measuring cups for at least a week, tracking it all in a food diary.

After that, you can eyeball amounts. But go back to weighing and measuring every few months to tweak your portion-size perception.

“Portions tend to get a little bigger and bigger over time,” Godwin said. 

To outwit your appetite, use a 10-inch dinner plate so portions don’t look too small and tempt you to return for seconds. Of course, you can’t exactly haul this equipment to restaurants, so keep eating out to a minimum or just eat less of what you’re given. Because no matter how much you think you ate, you’ve probably eaten more.

• “My body needs a detox every once in a while.”

In reality, you actually need to detox every day. The good news is, you don’t need to do anything special beyond eating a healthy diet. 

“Your body is well-endowed with the apparatus to take care of the job,” said David L. Katz, MD, co-author of “How to Eat: All Your Food and Diet Questions Answered.” 

Your liver, spleen, kidneys and gastrointestinal tract constantly filter toxins out of your system. They break down metabolic gunk such as fat molecules, spent red blood cells, urea (a byproduct of protein metabolism) and other waste products, all of which are expelled through poop, pee or sweat.

To keep these systems in good working order and so that you can continuously detox more efficiently, load up on fruits and veggies. Their high water and fiber content speeds waste through your GI tract. Get plenty of fluids, too, so that your kidneys can flush water-soluble byproducts through your system. You’re hydrated enough if you urinate every three hours and it’s pale or clear and odorless.

Regular exercise also helps keep your blood circulating through your arteries and delivers a robust supply of blood to your spleen, liver and kidneys. Meanwhile, avoid toxins by not smoking and steering clear of foods high in refined sugar and saturated and trans fat.

• “Calories don’t count if I drink them.”

The truth is, liquid calories count just as much, if not more, than solid food calories do. Unfortunately, they are less nutritionally satisfying.

“When people drink milk, fruit juice, Pepsi, Red Bull, a smoothie, or whatever beverage, they don’t compensate for those calories by reducing their food intake,” said Barry M. Popkin, Ph.D, a professor at UNC Gillings School of Global Health. 

In fact, adults down an average of 533 beverage calories per day, which has doubled over the past 30 years. 

Aside from nonfat milk to help reduce the risk of osteoporosis, avoid drinking calories. Stick to water or noncaloric beverages like unsweetened iced tea between meals. Additionally, realize that when you do drink something caloric, including alcohol, it won’t fill you up but it will fill you out. That is, unless you exercise more or make a conscious effort to account for the calories—for example, saying to yourself “this is lunch” while sipping a smoothie.

• “I’ll eat less if I skip breakfast.”

A major study analyzing the breakfast patterns of 12,316 men and women for five years found that breakfast skippers were more likely to have a higher body mass index than breakfast eaters. The breakfast eaters also set a healthier tone for the rest of the day, consuming fewer foods high in fat and sugar.

But the study also found you’ll only get that morning advantage if you start your day off with foods low in energy density, such as unsweetened hot or cold cereal, whole-grain bread, fresh fruit or nonfat milk. Otherwise, breakfast can backfire. 

Your overall daily calorie tally will be higher if you feast on the likes of pastries and breakfast sandwiches, which can lead to weight gain.