01/08/2014 12:39 pm ET Updated Mar 10, 2014

Yes, You Can Lose Weight Eating Nothing But McDonald's, But That's Not the Point

One week into the new year and we've got our first viral weight-loss story. The gist: "Man loses weight eating McDonald's-only diet." This particular angle on weight loss is far from groundbreaking. Remember the man who ate nothing but potatoes for 60 days in 2010 and lost more than 20 pounds? What about the man who subsisted on pizza for 30 days in 2009 and achieved similar results?

These victorious tales of weight loss are music to the fast-food industry's ears (interestingly, "the owner of the local McDonald's franchise was so interested he provided the 90 days of meals at no charge"). After all, it absolves fast-food giants of any responsibility, particularly at a time when nutrition and public-health advocates are consistently calling out industry's role in contributing to rising rates of chronic disease (from hypertension and heart disease to diabetes).

The man in question in this latest reincarnation of "eat fast food every day and lose weight" -- high-school teacher John Cisna -- is quoted as saying that the takeaway lesson from all of this is that health and weight are ultimately all about "our choices," a statement that completely overlooks how food environments (ubiquity of fast food, relentless advertising and an agricultural system that renders unhealthy foods more affordable) affect said choices. Is it really fair to talk about "choice" when a fast-food meal is artificially priced to be significantly cheaper than one consisting of healthier fare?

These news stories also foster the illusion -- one continually and willingly propagated by the food industry -- that weight loss and health are synonymous. Do calories play a role in weight management and metabolism? Of course they do. However, to claim that health is ultimately about caloric balance is disingenuous at best.

According to Fox 8 WGHP, Mr. Cisna states that he "tried to stay close to the recommended dietary allowances for nutrients like carbohydrates, proteins, fat calories and cholesterol," and that "by the 90th day, he lost 37 pounds and his cholesterol dropped from 249 to 170."

What about other health factors, such as the fact that some McDonald's items -- like the egg-white McMuffins -- are cooked in artificial trans fats? Mr. Cisna's added sugar intake must have been hefty, too, considering that, by his own admission, he ate the chain's sugar-laden oatmeal as well as ice-cream sundaes and cones regularly.

The American Heart Association recommends that adult men consume no more than nine teaspoons -- 36 grams -- of added sugar a day, and the World Health Organization announced plans in December to possibly cut sugar recommendations by half. Meanwhile, a 16-ounce McFlurry with M&M candies provides 128 grams of sugar (some are naturally occurring from milk in the soft-serve, but nevertheless an exorbitant amount of sugar is tacked on).

From a health standpoint, we must also think about what wasn't consumed during this 90-day experiment. A McDonald's-only diet doesn't contribute much in terms of fiber, omega-3 fatty acids, probiotics or the hundreds of phytonutrients found in minimally processed whole foods like beans, nuts, seeds, vegetables and fruits.

As for the irrevocable "proof" we've been provided to show that 90 days of eating McDonald's does not cause any negative health effects: total cholesterol doesn't tell the whole story. What about Mr. Cisna's HDL cholesterol? HDL-to-total cholesterol ratio? Triglycerides? Fasting blood sugar? Markers for inflammation? What about other consequences that can be harder to measure, such as the effect on his gut bacteria, or his risk for colon cancer?

These news stories mirror a culture where the calorie rhetoric is fixated on quantity and overlooks quality. From a strictly numerical standpoint, there is technically no difference between 300 calories of nacho-cheese Doritos and 300 calories of Granny Smith apples with almond butter. However, those two snacks' drastically different nutritional profiles have drastically different effects on our health.

There is one other disturbing angle to this story that isn't obvious upon first glance. If Mr. Cisna was able to lose weight (and "get healthier") eating nothing but McDonald's for 90 days, is there also subtext that food deserts shouldn't be a public health concern? That there is no need to advocate for healthier neighborhoods, since technically, people can meet their nutritional needs, lose weight and lower their cholesterol by eating Big Macs, ice-cream sundaes and fries?

Privilege is ultimately front and center here. Mr. Cisna could have stopped his fast-food diet at any point. These 90 days were not about a financial need to subsist on heavily processed fast-food fare. They were a gimmick, a fun experiment. Many Americans, however, are beholden to unhealthy eating out of necessity. We owe it to them to help build a healthier food system, rather than hold up fast-food chains as beacons of health while simultaneously chastising individuals for making "bad choices."