Definition of Weight Loss
Weight Loss: The reduction of body weight as the result of diet change or burning more calories through physical activity – ideally both. Weight loss is usually recommended for overweight or obese people with a waist circumference of more than 40 inches for men and 35 inches for…Read more
Explore Weight Loss research in the following databases:
PubMed Trip Cochrane*
*The Cochrane database requires users to enter the search term manually. Enter “weight loss”
Research Spotlight
The databases often return hundreds of medical studies for a single wellness approach. This section summarizes a sampling of five studies – providing just a taste of the available research.
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Long-Term Success of Weight Loss Drugs Depends on Exercise
An important, new study (by the University of Copenhagen, published in The Lancet) of people who used and then quit a weight loss drug revealed that those who exercised while using the drugs kept off far more weight after quitting the medication than people who didn’t work out. Those who had taken the drug without exercise regained 70% or more of the weight they’d lost—and most of the regained pounds were fat, not muscle. But people who exercised while taking the drug (about two hours of vigorous exercise weekly) maintained considerably more of their weight loss after they stopped the drug. Many remained at least 10 percent lighter than at the study’s start, and at least some of the weight they’d regained was muscle. The researchers concluded that this makes a very strong case for “the importance of adding exercise to a regimen that includes any GLP-1 medication.” This is important, since studies show that roughly half of users quit the drugs within a year because of their cost, side effects, etc
Access this study on weight loss - Intermittent Fasting and Calorie Counting Equally Effective for Weight Loss–But Former Easier to Adhere to
A year-long study (University of Illinois, 2023) compared the impact on weight loss of a compressed eating day (between noon and 8 PM) vs. cutting calories by 25% each day (and having to constantly count them). The finding: It’s just as effective to watch the clock as it is to watch what you eat. Both groups lost about 5% of their body weight after a year, but the researchers noted that focusing on when you eat not what “is an easier diet to adhere to.” They considered the findings exciting because they showed that people could stick with a daily model of intermittent fasting vs. fad diets where they constantly fall off the wagon.
Access this study on weight loss - Conventional Wisdom about Metabolism Is Wrong
It’s widely believed that people put on weight in middle age because their metabolism slows down and that women have slower metabolisms than men. A large 2021 study (6,500 people) indicates that those assumptions are wrong. Rather than metabolism slowing in middle age, there are four distinct phases of metabolic change: 1) infancy until age 1 (3% growth), 2) age 1-20 (metabolism slows about 3% a year), age 20-60 (it holds steady), and after 60 (metabolic rates decline 0.7% a year). So, for adults, metabolism slowdown doesn’t happen until after 60 and there are no real differences in metabolic rates for men and women. These findings have big implications for medicine and wellness.
Access this study on weight loss - Obesity Hurts the Brain
A 2020 study from Johns Hopkins and the University of California, Irvine found that people with a higher body mass index have less blood flowing to their brain, which might explain why obesity is tied to Alzheimer’s risk. Performing brain scans on 17,721 men and women, they discovered that the higher the BMI, the lower the blood flow to five regions of the brain that are especially vulnerable in Alzheimer’s disease: the temporal lobes, the parietal lobes, the hippocampus, the posterior cingulate and the precuneus.
Access this study on weight loss - Intermittent Fasting Cuts 550 Calories a Day
A 2020 study from the Univ. of Illinois-Chicago randomized obese men and women into three groups: those who ate an unrestricted amount of calories from 1–7 PM, those who ate unrestricted calories from 3–7 PM, and a control group that ate anything at any time of day. Both groups that practiced time-restricted fasting consumed, on average, 550 fewer calories each day and lost 3% of their body weight while seeing significant reductions in insulin resistance and oxidative stress. The researchers noted how significant the impact of intermittent fasting was and how simple: All you have to do is watch the clock.
Access this study on weight loss - Ultra-Processed Foods Seem to Be the Weight Gain Villain – Not Sugar, Fat, Carbs
A 2019 study from the NIH is the first randomized trial to show that ultra-processed foods drive people to overeat and gain weight compared to whole/less processed foods. Those on an ultra-processed diet ate 508 more calories a week, gaining two pounds over the two-week study period, versus those on the unprocessed diet who lost two pounds a week. Key aspect of the study: Each group ate the same amount of calories, sugar, fat, salt, carbs and fiber—and could eat as much as they wanted. Researchers found that those on the ultra-processed diet had lower levels of an appetite-suppressing hormone and higher levels of the hunger hormone.
Access this study on weight loss - Your Microbiome Impacts Whether You Can Lose Weight…Or Not
A 2021 study from the Institute for Systems Biology compared people who lost 1% or more of their weight each month on a weight-loss diet, compared with those whose weight didn’t budge—finding that the groups had different microbial DNA and bacteria in their microbiome. Those that lost weight had microbial DNA that allowed bacteria (especially Prevotella) to grow fast (these bacteria ate sugar/nutrients before the body could absorb them), while the weight-loss-resistant group had gut enzymes better at breaking down starches/fiber into sugars. More evidence that altering the microbiome is a path to weight loss.
Access this study on weight loss
Studies-in-Progress/Clinical Trials Underway
A clinical trial is any research study that assigns people to health-related interventions to evaluate the outcomes. “Interventions” include drugs, surgical procedures, devices, behavioral treatments, preventive care, etc.
- ClinicalTrials.gov: explore trials underway in the U.S.
- World Health Organization: explore trials happening across the globe. When you reach WHO’s search page, please type in “weight loss.”
Access all studies currently available for Weight Loss in these databases:
PubMed Trip Cochrane*
*The Cochrane database requires users to enter the search term manually. Enter “weight loss”
