Monday. According to a recent study by Orsama and colleagues, that’s the day when most people experience their maximum body weight. And your lowest body weight? That’s most likely to be recorded on Friday. 
 
 The weekend certainly seems to play some havoc on our energy balance. 
 
 The 7 day week cycle has an impact on many of our behaviors. Take sleep, for example. During the week, we get up regularly at the sound of our alarm, but come Saturday, the alarm clock may be turned off and you allow yourself to sleep in. Your physical activity level is also likely to oscillate based on the day; individuals who actively commute to work may become more of a couch potato on the weekend. People may also be more likely to go out and have a few drinks over the weekend. All these behaviors can have an impact on a person’s energy balance, and subtly, on their body weight. And apparently, that’s exactly what happens. 
 
 In the study published earlier this year, Orsama and colleagues explored the weekly rhythm of weight to understand the normal variation of weight which occurs during the week. The researchers analysed daily self-reported body weight in 80 adults (BMI: 20.0–33.5 kg/m2; age: 25–62 years). To avoid intra-day variation in body weight individuals were instructed to record their daily weight immediately after waking up and before breakfast. The length of each individual’s time series of recorded weight varied from 15 to 330 days. 
 
 As I’ve already summarized in the first couple of sentences, body weight tended to be highest following the weekend (Sunday/Monday) and lowest just before the weekend (Friday). 
 
 As a potential explanation of this weekly weight fluctuation, the authors propose that meal sizes and calorie intake tend to increase while physical activity tends to decrease during weekends. Indeed, many people who eat a clean diet during the week allow themselves a cheat day over the weekend. Evidence seems to favor such a flexible approach to diet management, by contrast to the all or none approach. The former approach allows you to enjoy some highly-favored but potentially calorie-dense foods in relative moderation, potentially increasing long-term adherence to a diet. By contrast, the latter approach, which outright forbids certain foods, may result in dietary boredom, and complete discontinuation of the healthy diet. 
 
 This also leads us to the other interesting finding in this study. Variation in body weight was also analysed according to whether the participants lost weight (greater than 3% reduction), gained weight (greater than 1% increase), or maintained weight (weight change between –3 and 1%). What is interesting, as illustrated in the figure below, is that the biggest fluctuation in weight occurred in those who lost weight over time. This would suggest that successful weight losers were allowing themselves some serious dietary leniency over the weekend. Maybe this is exactly what allowed them to persist on their respective diet for a longer duration. 
 
 What are the implications of this research? 
 
 First, if you like to regularly weight yourself, best to compare the same day of the week (and same time of day). 
 
 Secondly, allowing yourself a few indulgences over the weekend may in fact help you stick with eating better and managing your weight over the long term. 
 
 Peter 
 
 Reference: ||||| You've been eating well all week: oatmeal for breakfast, a salad for lunch and grilled chicken with vegetables for dinner. Then the weekend hits. Suddenly your taste buds want French fries at the bar and Mom's cheesy lasagna is calling your name during Sunday dinner. 
 
 Not to worry. A new study suggests small weight gains on weekends are normal, and as long as you can compensate during the week, indulging a bit may even help you lose weight long-term. 
 
 “There is a clear weekly rhythm to weight variation for most people,” says one of the study authors, Anna-Leena Orsama, a research scientist with VTT Technical Research Center of Finland. “On the weekends there is more variability and unpredictability in what we eat.” 
 
 The study, “Weight Rhythms: Weight Increases during Weekends and Decreases during Weekdays,” was published this week in the journal Obesity Facts. 
 
 The study 
 
 Researchers analyzed data from 80 adults, ranging in age from 25 to 62 years old, who recorded their weight each day after waking up. 
 
 The participants were grouped according to their weight changes over the study period: weight losers who lost at least 3% of their body weight; weight gainers who put on at least 1%; and weight maintainers who stayed in between those minimums. 
 
 The results 
 
 All three groups, the losers, gainers and maintainers, recorded higher weights on Sundays and Mondays than other days of the week. But those who successfully lost weight had lower weights during the week, with their lowest generally recorded on Friday. 
 
 This shows they managed to compensate for the weekend gain during the work week, researchers say. 
 
 Limitations 
 
 The sample size for this study was relatively small. Only 10 people were in the gain group; only 18 were in the loss group. The data was also all self-reported, meaning the study participants could have made a mistake or purposefully altered their recorded weights. 
 
 Also important to note is that the researchers are talking about slight caloric increases. This is not a free pass to eat your weight in cookie dough. 
 
 The takeaway 
 
 Long-term habits may make more of a difference than short-term splurges, the study authors say. And a flexible eating pattern - i.e., allowing yourself that brownie or beer on Friday night - may help you sustain overall healthy eating habits over time. Weight loss success depends primarily on your ability to compensate for those splurges on other days of the week. 
 
 “The big difference between those who gain weight over time and those who lose or maintain weight is directly related to the way they eat from Monday to Friday," said Cornell University behavioral economist Brian Wansink, one of the study authors. 
 
 "Some indulging during weekends makes no harm but for successful weight loss it is important to notice these rhythms and take steps to reverse the upward trends." ||||| Drinking diet soda doesn't do your waistline any favors, research is suggesting. 
 
 In a May 2016 study published in the journal JAMA Pediatrics , researchers studied over 3,000 pregnant women and their infants and found that mothers that frequently consumed diet beverages (drinks with artificial sweeteners) were two times more likely to have babies who were overweight or obese at one year after birth compared to women who consumed fewer artificially sweetened drinks. While the study doesn't prove that diet drinks and artificial sweeteners cause weight gain, it certainly isn't doing the trend any favors. 
 
 Another 2015 study published in the Journal of the American Geriatrics Society found that people who drank diet soda gained almost triple the abdominal fat over nine years as those who didn’t drink diet soda. The study analyzed data from 749 people ages 65 and older who were asked, every couple of years, how many cans of soda they drank a day, and how many of those sodas were diet or regular. 
 
 Those answers ended up being extremely predictive of abdominal-fat gain, even after the researchers adjusted for factors like diabetes, smoking and levels of physical activity. People who didn’t drink diet soda gained about 0.8 in. around their waists over the study period, but people who drank diet soda daily gained 3.2 in. Those who fell in the middle — occasional drinkers of diet soda — gained about 1.8 in. 
 
 That change in waist circumference is especially concerning because it highlights an unfortunate truth about weight distribution: the belly is a bad place for extra pounds. The kind that pads the abs from the inside, called visceral fat, is associated with increased cardiovascular disease, inflammation and Type 2 diabetes. 
 
 MORE Is Diet Soda Bad for You? 
 
 These results, which the study authors call “striking,” add to the growing body of evidence that no- and low-calorie sweeteners may come with health concerns. Though scientists are still puzzling through the mechanisms by which diet soda seems to have the unintended consequence of weight gain, they have some ideas. Sugar-free sodas contain substances that sweeten up soda at 200-600 times the sweetness of sugar. 
 
 As TIME has previously reported , some experts believe that artificial sweeteners trigger sweetness receptors in the brain, which cause the body to prepare itself for an influx of calories. Even though those calories don't arrive, the body still craves them, and that may cause people to ultimately eat more calories overall, putting them at a risk for weight gain. 
 
 "Regular sugar has caloric consequences," says the study's senior author Dr. Helen Hazuda, professor of medicine at the University of Texas Health Science Center at San Antonio. And one of those is that it triggers satiety — a sense of fullness or satisfaction. "Your body is used to knowing that a sweet taste means you are ingesting energy in the form of calories that, if you don’t burn them off, is going to convert to fat," she says. Artificial sweeteners, however, confuse our bodies and weaken the link in our brains between sweetness and calories. That, Hazuda says, can lead to weight gain and cravings for sweeter and sweeter treats. 
 
 There may be something else at work. A recent study in mice showed that artificial sweeteners actually changed the gut bacteria of mice in ways that made them vulnerable to insulin resistance and glucose intolerance — both of which can lead to weight gain. And other mice research suggests that artificial sweeteners are associated with a drop in the appetite-regulating hormone leptin, Hazuda says. Leptin is the hormone that inhibits hunger. 
 
 MORE 13 Ways to Stop Drinking Soda for Good 
 
 The Calorie Control Council, an association that represents the reduced-calorie food and beverage industry — including alternative sweeteners — disagreed with the study's findings. "The use of low-calorie sweeteners (LCSs) in weight management has been shown to be beneficial," the group said in a statement. "While approaches to treat obesity in older individuals is controversial, diet modifications can be a successful part of a weight-management program for older adults." 
 
 Researchers in the new study found that belly-fat gain was most pronounced in people who were already overweight. "People who are already at cardiometabolic risk because they have higher BMIs are really in double or triple jeopardy," Hazuda says. "When they think they’re doing something good by drinking artificially sweetened beverages, it’s actually totally counterproductive."
– For most of us, weekends are a time to relax and indulge—maybe through more sleep, more couch time, or more calories in the food and beverages we consume. The result is that we tend to weigh slightly more on Sunday and Monday, but then slightly less again by Friday, reports the Smithsonian. And enough of us do this that scientists say they've observed the general weight trend in a small study published in the journal Obesity Facts. The researchers analyzed the recorded daily weights of 80 adults ages 25 to 62 and found weight "increases begin on Saturday and decreases begin on Tuesday." Before we all fall into a pit of despair in the days leading up to Thanksgiving, one doctor stresses on PLOS' Obesity Panacea blog that it's not a bad thing to "cheat" diets and habits on the weekends. In fact, it "allows you to enjoy some highly-favored but potentially calorie-dense foods in relative moderation, potentially increasing long-term adherence to a diet." The study's authors agree, telling CNN that "some indulging" does no harm. (Meanwhile, if you want to lose weight, research indicates you shouldn't forgo fats.)