Liquid Calories

Listen to Katherine discussing juicing on National Public Radio’s Kojo Nnamdi Show on WAMU 88.5 FM.

Juicing is all the rage these days, with juice cleanses, celebrity juicers, and Starbucks opening its first Juice Bar. On National Public Radio’s Kojo Nnamdi Show, I discussed juicing and juices. Find the link below…

I’ve been drinking orange juice every morning of my life. You’d think I’d be sick of it by now. But every morning, I look forward to my “sunshine in a glass,” and it never disappoints. Especially on those occasions when it’s fresh-squeezed. I could live on the stuff. Just thinking of it makes me salivate!

But I save my juice for 4 ounces in the morning because, while it packs a nutritional punch, it also puts on pounds, and fast! Here’s how…

My client, Caroline, who was successfully losing weight, was disappointed one recent week that she didn’t lose weight as usual. It didn’t make sense to either of us. Her food intake was stellar. She was even a little more physically active than usual. It wasn’t until we reviewed her food diary thoroughly that we discovered the culprit was liquid calories, and they added up in a way that surprised her. In her case – as is the case with many of us  – that extra glass of wine or mixer, juice as a snack here and there, can add up in ways we don’t expect.

Liquid calories in just about any form, whether alcohol, juices, or sodas, are stealth calories. They come in undetected under the radar screen but have an impact that can be enormous. Scientific evidence is confirming that though these liquids count as calories, our bodies don’t detect them the same way they would if we were eating solid food. When we eat calories in the form of solid food, we naturally compensate by reducing the rest of our meal’s or day’s food intake. But when people ingest liquid calories, studies show, they don’t compensate for them by eating fewer calories.

“Fluid calories do not hold strong satiety properties, don’t suppress hunger and don’t elicit compensatory dietary responses,” says Richard D. Mattes, MPH, PhD, RD, Professor of Foods and Nutrition at Purdue University. “When drinking fluid calories, people often end up eating more calories overall.”

This may help explain the results of the Harvard Nurses Health Study of more than 50,000 women over eight years. The researchers found those who increased their intake of sugar-sweetened beverages, such as sodas or fruit punch, from one per week to one or more per day, increased their calories by 358 daily and gained significant weight. Women who reduced their intake cut their calories by 319 calories and gained less weight. Earlier studies demonstrated that consumption of sugar-sweetened soft drinks increased the likelihood of obesity in children, but this is the first finding from a long term observational study in adults.

The mechanisms controlling hunger and thirst are completely different, and liquids, even if they contain calories, don’t seem to satisfy hunger even if they quench your thirst. Physiologically, your thirst is quenched once your blood and cell volume is increased by water. This signals your brain that you are no longer thirsty.

Hunger is regulated in your stomach and intestines. While you’re eating, nerves in the stomach wall detect that it is stretching and send satiation signals to the brain. The intestines also release nerve regulators and hormones. At the same time, the hunger hormone, ghrelin, released by the stomach when it is empty, goes down. All of which help you feel satiated.

 There are several theories explaining why liquid calories cause lower satiety and increased overall calorie intakes, but it’s still not fully understood. First, cognitively, people have a harder time realizing that liquids count. Also, the mouth-feel of a liquid versus a solid may generate different signals, less time and involvement with food, and reduced psychological satisfaction. Finally, liquids, because they travel more quickly through the intestinal tract, alter the rate of nutrient absorption, which can affect satiety hormones and signaling. It’s likely that all of these reasons are relevant.

Emerging research is finding the hunger hormone ghrelin may play a physiological role.

 “When the number and type of calories are the same, the calories in liquid form won’t suppress ghrelin as effectively as if the same calories were in solid form,” says David E. Cummings, associate professor of medicine at the University of Washington and the Veterans Affairs Puget Sound Health Care System.

While Cummings hasn’t tested many types of fluids and their varying effects on ghrelin, other researchers have found drinking fluids may produce varying degrees of satiety, depending on what they contain.

It’s fairly well-established that alcoholic beverages and sugary liquids, especially sodas and fruit drinks aren’t completely registered or compensated for and simply add extra calories.

 “Some beverages cross over the line into being a food,” says Barbara J. Rolls, professor of nutritional sciences at Pennsylvania State University. She conducted studies which found people felt more satiated and consumed fewer calories when they had milk-based drinks at the beginning of a meal. The high protein levels in addition to cognitive beliefs about milk being a food may make it more satiating.  Also, fluids with food in them, such as soups, are very satiating.

 But most caloric fluids Americans consume are not satiating. When you consider that an appropriately sized meal is anywhere from 400 to 700 calories, and one Big Gulp is 640 calories, you understand the scope of the problem! A Starbuck’s Frappuccino can total anywhere from 300 to 600 calories. One glass of wine contains at least 100 calories. And one mixed drink can set you back 300 calories or more. Double or triple these numbers at any given party, tack on the calories in your meals, and you can understand how weight gain is the inevitable result.

My clients who have become aware of liquid calories have achieved impressive results. Take Bob Levey, former Washington Post columnist. Bob wrote about the importance of cutting out his daily lemonade in his successful weight loss effort. My other client, Julie, easily switched her daily Frappuccino to a skim coffee latte and saved 250 calories. My friend, Linda, slowly phased out her daily soda by adding more and more ice to it each week until she was only drinking water. She lost 30 pounds over a year.

 Most people find reducing liquid calories is an easy change. Since liquid calories don’t contribute to feelings of satiety, cutting them doesn’t lead to feelings of deprivation or hunger. And there are so many great substitutes. The one liquid that’s important to keep drinking is water. In the winter time, I love sipping water as herbal teas through the day. In the summer, it’s selzer with a twist of lemon or lime, and the occasional diet soda.

Of course, if we are mindful of our calorie intake, a moderate daily dose of wine or other caloric beverage can easily be integrated into our routines. The key is mindfulness and moderation.

Listen to Katherine discussing juicing on National Public Radio’s Kojo Nnamdi Show on WAMU 88.5 FM.