Reddit's Favorite Diet Trend Is Horrifically Outdated, Nutritionists Say

They're calling it the CICO diet — calories in, calories out. It's trendy, clickable, and so seductive. The diet says you can eat whatever foods you want — so long as you burn more calories than you consume.

"CICO will work regardless of what you're eating. Junk food, healthy food, fancy food, cheap food," one thread claims. "It doesn't matter. CICO is essentially the only thing that matters when it comes to weight loss."

But this strain of thinking has not only been done before (hello, where do you think the obsession over calorie counts came from in the first place?) but has been proven ineffective by scientists, nutritionists, and many a failed dieter.

Many users on Reddit are stubbornly sticking to the outdated regimen regardless.

The "subreddit" forums for weight loss conversation have been circulating CICO conversation, bragging of short bursts of weight loss and proliferating unhelpful and misleading threads. Few of these threads come from medical professionals or nutritionists, allowing those attempting to diet to proclaim their unproven beliefs to thousands of equally ill-informed readers. They also all contradict the growing body of research that shows weight loss diets don't work — and actually cause additional weight gain in the long run.

There are a few things wrong with the CICO diet way of thinking.

1. It assumes a smaller body is a healthier body.
In many cases, this isn't true at all. Every body has a "set point," which is a weight at which it functions best. If your weight loss is plateauing, it's likely you're in the lower range of the 10-20 pound flux that is your set point.

If you're in a calorie deficit and forcing your body below your set point, you're actually subjecting yourself to a ton of stress and releasing hormonal havoc into your body. These hormones and reactions begin to work against your weight loss attempts, encouraging your body to put on more weight than you lost.

If you don't believe us, believe the science — there's a huge body of research behind this idea called set point theory, and it has wide acclaim and support from leading nutritionists.

2. It neglects to account for nutrition apart from calories.
As any nutritionist will tell you, not all calories are created equal. Imagine living on an all-Cheetos diet, for example. You'd obviously be protein-deficient, low in dietary fats, and deficient of almost all other nutrients. But according to the CICO diet, if you ate few enough Cheetos, you'd be okay.

"Eating all junk, but keeping it low-calorie, will still wreak havoc on things like your skin, your mood, your gastrointestinal functions," Dawn Jackson Blatner, RDN, told Yahoo. It'll also wreak havoc on your metabolism.

3. It assumes all bodies of the same weight, height, and activity level are the same.
Not all bodies are the same — since all bodies are made from inherently different DNA. Your genes not only affect your eye color, height, and shoe size, but also play a pivotal role in how you digest food, how you metabolize energy, and how your body regulates its weight.

Leading media outlets like The New York Times are receiving criticism on Reddit from CICO advocates who claim that the Times is overgeneralizing when they say everyone is different and there's no real way to calculate your calorie needs.

"Um, it's called your total daily energy expenditure?" one dismissive Reddit user rebuked. "Very easy to calculate online."

Not really, though. Online calorie calculators that use your height, weight, and activity level to calculate a daily calorie number are also seriously generalizing. No two people's calorie needs are the same, and no two days produce the same calorie need. Think about it. Some days, you're lying in bed all day and other days you walk to work and back. Clearly, your body is not using the same amount of energy on both days. It's also probably dealing with different hormonal levels, gut bacteria, neurotransmitter responses, etc.

It's literally impossible to calculate the exact number using today's science.

There are so many factors that affect how your body metabolizes calories every day — and a CICO diet really isn't considering any of them. For example, here are a few 'healthy' habits that are slowing down your metabolism right now.