Is Staying Lean Harder Than It Was 30 Years Ago?

Is Staying Lean Harder Than It Was 30 Years Ago?


Is Staying Lean Harder Than It Was 30 Years Ago?

Staying lean, tight, and healthy has never been easy. After the age of 30, a number of factors, like hormonal changes and the gradual loss of lean body mass, makes staying a healthy body weight more challenging. In other words, it takes work to stay lean! But has it always been that way?

We’re constantly reading about the obesity epidemic and how being overweight and obese is becoming the norm. According to 2012 statistics from the Centers for Disease Control and Prevention, almost 70% of Americans are overweight or obese, a disturbing statistic when you consider how closely obesity is linked with type 2 diabetes, heart disease, and some forms of cancer.

Here’s a statistic that might shock you. Prior to 1980, only one in ten people were obese.  That’s an alarming increase! Many experts try to blame this unprecedented rise in obesity on supersized portions, the wrong dietary choices, and lack of exercise, but according to a new study published in the journal Obesity Research and Clinical Practice, there could be more to the story.

Staying Lean: What New Research Shows about Obesity Then and Now

In a recent study, researchers looked at dietary habits of almost 37,000 Americans over a 37-year period, beginning in 1971. They also looked at levels of physical activity among more than 14,000 people from 1988 to 2006.

The results were surprising. They found people who ate a similar amount of calories and exercised roughly equal amounts today as people did in the mid-1980’s weighed about 10% more. Even though exercise and food intake was roughly similar between the two groups, people today are likely to weigh more.

What does this suggest? According to the authors of the study, factors other than diet and lack of exercise are contributing to the obesity epidemic. Simply put, it’s harder to maintain a normal body weight today than it was 30 to 40 years ago. The question is why?

Experts have put forth a number of theories to explain this discrepancy. One of the most compelling is the idea that the bacteria that live in our gut, our so-called microbiome, has changed over the last 30 to 40 years. The bacteria that make their home in the dark recesses of our intestinal tract play an important role in health. Research suggests they not only help maintain healthy digestive function – but the same tiny bacteria play a role in immune health and, also influence body weight.

How might gut bacteria impact your body weight? For one, the type of bacteria you have in your gut influences nutrient absorption and how much energy you’re able to extract from the food you eat. Some bacteria seem to make it easier for you to absorb calories from the food you eat.

Some studies show people who are overweight or obese have a different composition of gut bacteria and a less diverse bacterial population than those who are lean.  Interestingly, gut bacteria implants may be on the horizon to help with weight loss.

Staying Lean: Why Are Gut Bacteria Changing?

The question is why the bacteria in our guts have changed over the last few decades. One possibility is we’re exposed to more antibiotics from food sources. Factory-farmed animals are injected with antibiotics to increase their size. When you eat meat from these animals, you consume low levels of these antibiotics, which may be enough to change the composition of the bacteria in your gut. It’s also possible the chemicals we’re exposed to in processed and packaged foods affect gut bacteria as well.

Some experts blame it on chemicals in the environment, like BPA in plastics. Thirty to forty years ago, fewer things were packaged in plastic and most people were probably exposed to much lower levels of BPA – not so today and it may be impacting body weight. A study involving Chinese school children showed kids with higher BPA levels in their urine had higher body mass indexes. Most adults and children have BPA in their urine and blood, and with so many foods and beverages packaged in plastic, it’s not surprising.

Other factors that may be contributing to the higher obesity rate are medications. More people take medications linked with weight gain these days. According to Dr. Louis Aronne, M.D., director of the Comprehensive Weight Control Center at Weill Cornell Medical College, up to 15% of weight-related problems may be related to medications. These days, more people are taking anti-depressants than 30 years ago and the majority of these medications cause weight gain.

Antidepressants aren’t the only drugs that impact body weight. Medications used to treat diabetes, migraine headaches, and seizures cause weight gain, as do steroids. Also, many people don’t realize that some antihistamine medications used for allergies increase appetite and can lead to weight gain.

Another contributing factor could be stress. According to a study carried out by researchers from Carnegie Mellon University, stress levels among Americans has increased by between 10 and 30% over the past 30 years. Simply put, life is more complicated and difficult to balance. We’re constantly exposed to bad news that travels at lightning speeds across the internet.

How might stress impact body weight? For one, some people eat more when they feel stressed. Plus, chronic stress increases production of stress hormones. One stress hormone, in particular, cortisol, is linked with abdominal weight gain and obesity. Stress can also impact sleep, and research shows a lack of quality sleep is a risk factor for weight gain.

The Bottom Line

No doubt, the easy availability of fast food, the convenience of packaged foods, and lack of exercise contribute to weight gain and obesity but, as this study suggests, it may not be the whole story.

Fortunately, some of these non-diet, non-exercise factors that potentially impact obesity are modifiable. You can limit your exposure to BPA by purging your refrigerator and cabinets of plastics, avoid taking antibiotics unless you truly need them, nurture your gut with probiotic bacteria from yogurt and other sources, and only eat organic meat from animals that haven’t been exposed to antibiotics. Finally, find ways to better deal with stress, like yoga and meditation.

Finally, don’t forget the basics – regular exercise, both strength and aerobic training, a whole food diet, and getting adequate sleep all make it easier to control your body weight.



Health United States 2014. Centers for Disease Control and Prevention

OECD. “Obesity Update”

Environmental Health 2012, 11:79  doi:10.1186/1476-069X-11-79.

Scientific American. “How Gut Bacteria Help Make Us Fat and Thin”

WebMD. “Are Your Meds Making You Gain Weight?”

New York Daily News. “Stress levels soar in America by up to 30% in 30 years”

Business Insider. “It Was Easier to be Thin in the 80s”


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One thought on “Is Staying Lean Harder Than It Was 30 Years Ago?

  1. One factor not mentioned that I can’t help but think is important is ‘daily activity’: how much physical movement we get aside from exercise.

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