A Calorie is Not Just a Calorie

A Calorie is Not Just a Calorie

In 1918, when Lulu Hunt Peters published her best-selling Diet and Health: with key to the calories, she was offering American women her personal solution to being overweight. After Lulu earned her medical degree from University of California in 1908 she decided to use calorie-counting and self-control to cure her life-long struggle with obesity. Her solution helped her shed 32 kilograms (70.5 pounds!) and America’s hard-to-shake belief that a calorie is a calorie is a calorie was launched.

For decades, nutritionists said to lose weight and keep it off, take in fewer calories daily than you burn. And while that is kind of true, we’ve begun to unravel the more complex ways that different nutrients and substances affect your metabolism, appetite, blood sugar, gut biome, immune system and inflammation level. As a result, we now know that the source of your calories (and when you eat them) matters for many aspects of your health and wellbeing: your weight, your cognition, your mood, your cardio system, your digestion, your microbiome, your longevity, even your sex life!

A hundred calories of the following nutrients exert wildly different effects on the body.

  • 100 calories of lean protein: Found in fish and skinless poultry, legumes, nonfat dairy, tofu, nuts, egg whites and whole grains, lean proteins help control appetite and weight, steady blood sugar levels and reduce your risk of heart disease and type 2 diabetes and build muscle.
  • 100 calories of red and processed meat: These boost inflammation, damage weight-controlling gut bacteria, increase your risk of heart disease and some cancers and can contribute to dementia and sexual dysfunction.
  • 100 calories of complex unrefined carbohydrates: Found in 100 percent whole grains (1/2 cup brown rice) and fresh produce (5 cups of broccoli or 1 1/4 cups blueberries), complex carbs and the fiber they contain support “good” gut bacteria. That helps control weight, protects the production of mood-influencing neurotransmitters like serotonin; reduces body-wide inflammation that triggers heart disease; bolsters your immune system; helps protect your digestive system from IBD and IBS and more!
  • 100 calories of simple carbohydrates: Refined sugars, sugar syrups (high fructose corn syrup for example), white bread, pastas, sweet sodas and sugar-added juices, snacks, desserts and baked goods are sure-fire proof that a calorie is NOT a calorie—despite the lobbying efforts of the sugar industry to convince the public added sugar is not a serious health risk and trigger for obesity. These carbs directly contribute to the development of inflammation, insulin resistance, obesity, type 2 diabetes, heart disease and promote killer belly fat.
  • 100 calories of EVOO: Healthy fats like mono- and polyunsaturated fats found in olive oil and sunflower oil and omega-3 fatty acids like DHA (in salmon) and ALA (in walnuts) help you achieve a younger RealAge inside and out by reducing inflammation and promoting a healthy gut biome (making it easier to control your weight), keeping arteries clear and helping prevent wrinkles.
  • 100 calories of saturated or trans fat: Sat fat is found in animal protein (especially in red and processed meats), tropical oils, dairy products and eggs—all calorie-dense foods that contribute to weight gain. Excess intake raises artery-clogging lousy LDL cholesterol levels. It is also associated with foods (like lunch meats) that boost body-wide inflammation—a sure risk for a wide range of diseases.
  • Trans fats—also called partially hydrogenated fats—are truly destructive. They turn up in prepared and baked goods and a Harvard study found for every 2 percent of calories from trans fats consumed daily your risk of heart disease goes up 23 percent. (That means in an 1800-calorie-a-day diet every 36 calories (4 grams) of trans fats you eat takes you that much closer to a heart attack.)

So, the next time you take a bite, remember, it’s not just how many calories you consume, but it’s the foods that contain those calories that make a difference to your weight and your overall health.

Medically reviewed in February 2019.

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