WHAT IS THE 5-2 DIET?
The 5-2 diet is a fast diet that is a popular way to lose weight by eating normally for 5 days per week and eating very restricted calories on the other 2 days. The fasting days should not be back-to-back; there should be at least 1 normal eating day in between them.
PROCEDURE During your fast days, you can eat, but not very much.
Women get 500 calories per day; men get 600. Depending on age, gender, and how active you are, you could need three or four times as many calories.
The Fast Diet encourages you to eat lean protein, vegetables, and fruit on fasting days, usually as two small meals plus a few snacks. You will drink lots of water and may also have calorie-free beverages such as tea, coffee (no milk or sugar), and club soda. On your 5 "off days," you can eat anything. Surprisingly, the research team that studied the diet found that people didn’t gorge themselves on off days.
The Fast Diet strongly discourages drinking alcohol on fasting days and suggests that if you drink on your "off days," you drink only in moderation. Once you reach your weight loss goal, 1 day of fasting per week is recommended for maintenance.
WARNING If you have diabetes, this is not the weight loss plan for you. It could be dangerous, especially if you take medicine, and lower your blood sugar into unsafe -- even deadly -- territory. For others, some early studies show it may help improve some risk factors for heart disease, including blood pressure and cholesterol. However, any weight loss plan that drops the pounds is likely also to have this effect.
ADVANTAGES
1: Increase your metabolic rate to help you lose weight EXPERIMENT--In a recent study, researchers at the Institute for Clinical and Experimental Medicine in Prague decided to test this idea by feeding two groups of type 2 diabetics meals with the same number of calories but taken as either two or six meals a day. Both groups ate 1,700 calories a day. The "two meals a day group" ate their first meal between 6:00 a.m. and 10:00 a.m. and their next meal between noon and 4:00 p.m. The "snackers" ate their 1,700 calories as 6 meals, spread out at regular intervals throughout the day. Despite eating the same number of calories, the "two meal a day" group lost, on average, 3 pounds more than the snackers. Contrary to what you might expect, the volunteers eating their calories spread out as 6 meals a day felt less satisfied and hungrier than those sticking to the two meals.
CONCLUSION--The lead scientist, Dr. Kahleova, believes cutting down to two meals a day could also help people without diabetes who are trying to lose weight.
2: Longevity
EXPERIMENT--In one early study from 1945, mice were fasted for either one day in four, one day in three, or one day in two. The researchers found that the fasted mice lived longer than the control group and that the more they fasted, the longer they lived. They also found that, unlike calorie-restricted mice, the fasted mice were not physically stunted.
CONCLUSION--Not only does fasting extend their lifespan, but it also increases their "health span”, and the amount of time they live without chronic age-related diseases.
DISADVANTAGES When you dramatically reduce your calorie intake, you will lose weight. But it can also cause all kinds of health problems, including muscle loss. Further, when you start fasting, your body goes into conservation mode, burning calories more slowly.
Keep in mind that the initial weight lost on a fast is primarily fluid or "water weight," not fat. And when you go back to eating, any lost weight usually gets a return ticket. Not only do most people regain weight loss fast, but they also tend to add a few extra pounds because a slower metabolism makes it easier to gain weight. Worse, the weight that is regained is likely to be all fat -- lost muscle has to be added back at the gym.
Side effects of fasting include dizziness, headaches, low blood sugar, muscle aches, weakness, and fatigue. Prolonged fasting can lead to anemia, a weakened immune system, liver and kidney problems, and irregular heartbeat. Fasting can also result in vitamin and mineral deficiencies, muscle breakdown, and diarrhea.
The risks get more complicated and severe the longer you stay on a fast, or if you repeatedly go on fasts.
ETHICALS To some extent, the fast diet goes against humanity. "It's human nature for people to want to reward themselves after doing very hard work, such as exercise or fasting for a long period, so there is a danger of indulging in unhealthy dietary habits on non-fasting days," says Dr. Hu.[6] In addition, there's a strong biological push to overeat following fasting periods. Your appetite hormones and hunger center in your brain go into overdrive when deprived of food.
Skipping meals and severely limiting calories can be dangerous for people with certain conditions, such as diabetes. People who take medications for blood pressure or heart disease also may be more prone to electrolyte abnormalities from fasting. Also, says Dr. Hu, ‘we live in a toxic, obesogenic food environment[6]’. So, you'll need a strong social support network to endure very low-calorie days over the long haul.
References
[1]LienandVancerHeiden(2019)Aframeworkforexamininghowdietimpactstumormetabolism. Nature Reviews Cancer, https://doi.org/10.1038/s41568-019-0198-5
[2] KathleenM.Zelman,MPH,RD,LD,“DietMythorTruth:FastingIsEffectiveforWeightLoss”, NOURISH. <https://www.webmd.com/diet/features/diet-myth-truth-fasting-effective-weight-loss#1>
[3] “Notsofast:Prosandconsofthenewestdiettrend”,July31,2019. <https://www.health.harvard.edu/heart-health/not-so-fast-pros-and-cons-of-the-newest-diet-trend>
[4] “KetogenicDietMarketSize,Share&TrendsAnalysisReportByProduct(Supplements,Snacks,Beverages), By Distribution Channel (Supermarket/Hypermarket, Specialist Retailers, Online), By Region, And Segment Forecasts, 2020 – 2027”, September 2020. <https://www.grandviewresearch.com/industry-analysis/ketogenic-diet-market>
[5] LisaSchweitzer,“TheFastDiet”,April19,2021. <https://www.webmd.com/diet/a-z/fast-diet-review>
[6] Mosley,M.,&Spencer,M.(2015).TheFastDiet-Revised&updated:Loseweight,stayhealthy, and live longer with the simple secret of intermittent fasting. Simon and Schuster.
Assessed and Endorsed by the MedReport Medical Review Board
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