Latest news with #TimeRestrictedEating
Yahoo
30-06-2025
- Health
- Yahoo
Research Says This Way Of Eating May Impact Your Fertility—Doctors Reveal The Truth
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Time-restricted eating (TRE) is having a moment in the sun, to say the least. The eating method—which involves consuming all your daily calories within a set number of hours—can help manage weight, but it may impact another unexpected aspect of your health: your fertility. New research has shown that TRE, a form of intermittent fasting (IF), may improve fertility for those with polycystic ovary syndrome (PCOS). A 2025 review in Metabolism Open examined three studies to determine the relationship between IF, fertility, and PCOS and found that IF helped those with PCOS achieve more predictable ovulation schedules, which can increase the likelihood of pregnancy. Plus, since fasting can help with weight loss, it can potentially improve fertility for those who are obese and may have hypertension and high cholesterol, which can negatively affect fertility, says Joshua Hurwitz, MD, an OB-GYN and reproductive endocrinologist at Illume Fertility in Connecticut. However, fasting can also lead to nutritional deficiencies, which may disrupt one's hormonal balance and decrease egg quality, according to a 2024 study in Cureus Journal of Medical Science that looked at the association between nutritional deficiencies and subfertility. "Human health should be optimal going into pregnancy, and that can be hard to achieve when you are in a caloric deficit,' says Brittany Brown, RD, the founder of Feeding Babies, Nourishing Souls in Nova Scotia, Canada. So, what's the real correlation between fasting and fertility? Experts weigh in on TRE and how it can affect your chances of conceiving. Meet the experts: Joshua Hurwitz, MD, is a board-certified OB-GYN and reproductive endocrinologist and partner at Illume Fertility in Connecticut. Brittany Brown, RD, is the founder of Feeding Babies, Nourishing Souls in Nova Scotia, Canada. Suzanna Chatterjee, MD, is an OB-GYN based in Russellville, Arkansas. Eve Feinberg, MD, is a reproductive endocrinology and infertility specialist at Northwestern Medicine. Mel Spinella, RD, is a New York-based dietitian specializing in fertility and pregnancy nutrition and the founder of Well by Mel Nutrition. A 2023 study in Free Radical Biology and Medicine looked at older mice to see how intermittent fasting impacts reproduction, and found that one month of fasting every other day improved the quality of developing eggs. The fasting lowered the amount of free radicals, molecules that can interfere with cellular processes, including cell division and reproduction, says Brown. Still, Brown points out that this study was done in mice, and there's not enough evidence yet to claim that fasting could have the same effect on humans. 'Future research will hopefully uncover how this works, but for now, we need more data before making recommendations," she says. A 2021 study in the Journal of Translational Medicine looked at 15 women between the ages of 18 and 31 who didn't ovulate. They participated in time-restricted feeding for five weeks, and afterward, 11 of the 15 participants experienced improved menstrual regularity. Many people with PCOS produce high levels of insulin, which can lead to excess male hormones in the body (such as testosterone), preventing ovulation, Suzanna Chatterjee, MD, an OB-GYN based in Russellville, Arkansas explains. Eating stimulates insulin, so with fewer meal times, those with PCOS could experience fewer spikes of insulin, which could help manage those excess hormones. TRE may help restore ovulation and improve fertility outcomes without the need for medication for those with PCOS, adds Eve Feinberg, MD, a reproductive endocrinology and infertility specialist at Northwestern Medicine. Still, fasting won't help everyone with PCOS—in the aforementioned study, four of the 15 women with the condition didn't experience better menstrual regularity. So, more research is needed on the connection between PCOS and fasting. Those with obesity are predisposed to have conditions such as hypertension, high cholesterol, and diabetes, which can 'impair natural fertility, as well as lower the success rates of fertility treatment,' says Dr. Hurwitz. 'Even a modest weight loss of 5 to 10 percent can improve ovulation and hormone balance.' Still, weight loss is only one piece of the puzzle. 'Not everyone who is overweight will have trouble conceiving,' and vice versa, he adds. Plus, studies on TRE's effectiveness as a weight loss tool are conflicting. A 2021 study in Nutrition & Diabetes, which followed 78 men and women with obesity, found subjects had 'meaningful weight loss' after following a TRE plan for eight weeks. But a 2023 study of 547 adults over six months in the Journal of the American Heart Association found that TRE did not help subjects lose weight. So, more research is needed. Experts say those with PCOS and those who are obese may benefit from TRE. But for the general population, there are other better ways to improve one's fertility, such as exercising and eating healthy, balanced meals. 'Eating enough, especially nutrient-dense foods throughout the day, is essential for a healthy menstrual cycle,' as well as ovulation, says Mel Spinella, RD, a New York-based dietitian specializing in fertility and pregnancy nutrition and the founder of Well by Mel Nutrition. Brown also advocates for a more natural, eat-when-you're-hungry approach to mealtimes for those who are actively trying to conceive—even for those with PCOS—and particularly once pregnancy is possible or confirmed. 'Reliable and consistent energy intake is essential for reproductive health, especially in the early moments of pregnancy,' she says. She says that her female clients generally find more success conceiving when they follow less restrictive diets that focus on consuming healthy foods. Plus, the research on fasting and fertility is still in the early phases. 'Ultimately, there is a need for large-scale, long-term randomized control trials to truly understand the long-term impacts of TRE on fertility,' Spinella says. When it comes to intermittent fasting, there are a ton of different schedules breaking down when to eat, from the more flexible 14:10 (14 hours of fasting and 10 hours of eating), to the more restrictive 20:4 plan (20 hours of fasting and four hours of eating). Brown says intense schedules like 20:4 can make it difficult to meet daily nutrient needs, which are essential before getting pregnant. Meanwhile, a 12:12 approach is more flexible and easier to follow for success. For instance, eating only between 7 a.m. and 7 p.m. might naturally reduce late-night snacking on ultra-processed foods without being overly rigid. However, Dr. Chatterjee recommends following a 16:8 schedule, particularly for women with PCOS who are hoping to regulate their cycle. Before beginning any fasting schedule, it's always recommended that you check in with your medical provider to see what they think, Dr. Hurwitz says. At the end of the day, everyone is different and 'there's no one-size-fits-all answer,' to how your body will feel during your fertility journey, Brown says. The way you eat is totally up to you and what will make your body feel best. 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Health Line
12-05-2025
- Health
- Health Line
3-Month Intermittent Fasting Program Led to Significant Weight Loss
A 3-month time-restricted eating (TRE) protocol resulted in up to one year of sustained weight loss in people with overweight or obesity. Adhering to an 8-hour window of eating led to greater weight loss than eating throughout the day, whether early or late. Researchers say that TRE may lead to lasting behavioral and physiological changes that may aid long-term cardiometabolic health. New research suggests that a three-month protocol of time-restricted eating may help people with overweight and obesity lose weight and maintain that loss for at least one year. Time-restricted eating (TRE), a form of intermittent fasting, has gained popularity in recent years to aid weight loss. The idea is simple: instead of limiting what you eat, limit when you eat. Individuals who practice TRE typically choose a daily eating window of 8 to 12 hours. The goal is to reduce snacking and overall calorie intake by avoiding food outside the designated window. While early research on TRE remains limited, new findings presented at the 32nd European Congress on Obesity in Malaga, Spain, on May 11–14, suggest it could be a useful strategy for improving long-term cardiometabolic health. 'TRE offers a simplified and time-efficient alternative to traditional dieting. It eliminates the need for calorie counting and food tracking, which are common barriers to long-term adherence,' said lead investigator Jonatan R. Ruiz, PhD, professor in the department of Sport Sciences at the University of Granada. 'Our findings support the notion that behavioral simplicity enhances sustainability,' he told Healthline. Ruiz's team also observed that weight loss occurred regardless of when participants scheduled their eating window, suggesting that the approach offers considerable flexibility and can be adapted to fit individual lifestyles and routines. TRE led to long-term weight loss The research builds on a previous randomized controlled trial of TRE conducted by the same team, with results published in Nature Medicine earlier this year. That study found that narrowing the eating window from 12 to 8 hours per day led to weight loss and improvements in cardiometabolic health. The latest findings introduce a significant long-term follow-up period, offering insight into whether those health benefits are sustained over time. However, the research has not yet been submitted for peer-reviewed publication. The study was a randomized controlled trial that followed 99 adults with overweight or obesity for 12 months in Granada, Spain. The cohort was evenly split between males and females, with an average age of 49. Participants were randomly assigned to one of four groups for three months: Habitual eating: Continued regular eating patterns, with a window 12 or more hours Early TRE: An 8-hour eating window starting before 10:00 a.m. Late TRE: An 8-hour eating window starting after 1:00 p.m. Self-selected TRE: Participants chose their own 8-hour eating window All groups, including the habitual eating group, took part in a Mediterranean Diet education program. After the 12-week intervention, all TRE groups lost significantly more weight than the habitual group — between 3.5% and 4.5% of body weight (about 8 pounds), compared to just 1.5% (3 pounds) in the habitual group. Anthropometric measurements showed greater improvements in waist and hip circumference among the TRE groups. The early TRE group had the most substantial reductions, more than 1.5 inches at both sites. The late and self-selected groups saw similar, though more modest, changes. Meanwhile, the habitual group lost less than half an inch in either measurement. The most notable results came during the 12-month follow-up, which assessed the durability of those outcomes. Once again, all three TRE groups outperformed the habitual group. While the habitual group regained about one pound, participants in the TRE groups maintained modest weight loss. Both the early and late TRE groups sustained roughly 2% weight loss, and the self-selected group retained a 0.7% reduction. Waist and hip outcomes varied by group. The late TRE group showed the greatest improvements, with more than two inches lost at the waist and 1.3 inches at the hips. In contrast, the habitual group gained roughly an inch around the waist. The early and self-selected TRE groups maintained reductions as well, but those changes were not statistically significant. 'Most prior studies on TRE have focused on short-term outcomes, often ranging from 4 to 12 weeks,' said Ruiz. 'Our research provides one of the few datasets that includes long-term follow-up after the intervention, and it demonstrates that the initial weight loss benefits are largely maintained over time.' Adherence rates — the proportion of individuals who were able to stick with the TRE protocol — were also noteworthy, ranging from 85% to 88%. Long-term adherence to any diet is often challenging, so these findings are promising for the potential of TRE. 'We believe this is due to the low cognitive and behavioral burden of TRE compared to traditional calorie-restriction diets. Participants did not need to count calories or eliminate specific foods — they simply adjusted the timing of their meals,' said Ruiz. Long-term TRE benefits, safety not well understood Despite the growing popularity of TRE as a form of intermittent fasting, evidence related to weight loss and long-term health benefits is still lacking. 'There is a good deal of conflicting information on the effect of time-restricted eating on weight loss,' said David B. Sarwer, PhD, director at the Center for Obesity Research and Education. Temple University and a spokesperson for the Obesity Society. Sarwer was not affiliated with the research. 'While these results are encouraging, it is very important that when an individual is considering a time-restricted approach to eating, or significantly decreasing caloric intake, his or her physician believes it is a safe approach,' he told Healthline. A 2023 review of TRE evidence concluded that while many studies show potential benefits, the effects are typically small, and that larger, multiyear trials, especially in healthy populations, are still needed. TRE has been associated with improvements in: weight gain fat mass glucose intolerance insulin resistance fasting glucose malabsorption inflammation TRE is not without its critics either. A controversial research presentation at the American Heart Association's Scientific Sessions in 2024 suggested that TRE was associated with a 91% higher risk of death from cardiovascular disease. However, as a retrospective study, it cannot establish causality, and it's unclear whether TRE itself was responsible for the increased risk. Side effects of TRE are also possible, including: hunger headaches lightheadedness fatigue dehydration Some people, including those over 75 years of age or pregnant, should not try TRE. As Sarwer pointed out, anyone beginning TRE should consult their physician. 'For an individual with weight-related health problems such as type 2 diabetes or hypertension, decreasing intake or not eating at all for extended periods of time can lead to suboptimal control of those conditions and unwanted side effects throughout the day,' said Sarwer. Despite these caveats, TRE may still be an appealing and effective aid for weight loss and cardiometabolic health for many people. 'We hypothesize that TRE may induce lasting changes in behavioral patterns and circadian alignment, which persist beyond the active intervention. Restricting food intake to a consistent daily window could reinforce circadian rhythms, improve metabolic efficiency, and reduce late-night eating, which is often associated with excess caloric intake and weight gain,' said Ruiz.
