Only 11% of Americans correctly estimate their ideal daily calorie requirements, according to one survey. The rest of us tend to overestimate, says Bonnie Taub-Dix, RD, a spokesperson for the Academy of Nutrition and Dietetics. Let's say you assume that consuming 2,000 calories per day will allow you to reach your target weight, but it really takes 1,800: Those extra 200 are enough to keep an additional 20 pounds on your frame. 
“Intermittent fasting can be really challenging if you have an ever-changing schedule,” adds Hultin. “If you're traveling and crossing time zones, it could be very difficult to follow. It might be best for people with more stability in their lives.” Intermittent fasting isn’t safe for people with type 2 diabetes, children, pregnant or lactating women, or anyone with a history of an eating disorder.

When it comes to the "best" diet for most people, this one consistently ranks at the top of every list. If you can't afford a cruise to the Mediterranean (yet!), at least you can eat like the beautiful, long-living, and famously healthy people from the region. The Mediterranean diet teaches you to eat like a Sardinian, one of the "blue zones" identified by researchers as having a high number of people living past 100—by eating more fish, olive oil, healthy fats, and fresh vegetables. The point is to have not just a longer life but also a healthier and happier one, whether you're trying to lose weight or not. (Really—research shows that you can reap the benefits of the Mediterranean diet without cutting calories.)

If you're not a fan of meat, you may do better on a weight-loss program that emphasizes fruits and vegetables. A 2012 study published in The Journal of the Academy of Nutrition and Dietetics found women over 50 were more successful at keeping the weight off when they followed diets that increased their intake of fruits and vegetables and ate less meat and cheese. Good weight-loss programs with an emphasis on fruits and vegetables that might help women over 50 lose weight include the DASH diet, the Mediterranean diet and the Mayo Clinic diet.
With this eating style, you’re looking at a lot of menu planning and preparation. A review published in August 2017 in Nutrients suggests the diet could lead to weight loss, but the Academy of Nutrition and Dietetics warns the plan could also cause certain nutrient deficiencies, such as in calcium and vitamin D. (3,4) And, therefore, according to an article published in the January–February 2016 issue of the Royal Australian College of General Practitioners, anyone at risk for osteoporosis should avoid it. (5)

Too little sleep or too much sleep can throw your stress and regulatory hormones out of whack, and may lead to weight gain. A single night of sleep deprivation can increase levels of ghrelin (a hormone that promotes hunger), making you more likely to overeat the next day. Reduced sleep may also lead to fatigue during the day (duh) and less physical activity, which may be another reason why people who regularly don't get enough sleep tend to gain weight.
Similarly, just because snacks like blue chips don’t look like the greasy potato chips you know to avoid, don’t assume they’re a healthier option. “Yes, blue corn contains the antioxidant anthocyanin,” explains certified culinary nutritionist Trudy Stone. “However, much of the good stuff gets baked away during the process of creating the chips that very little nutritional value is left—leaving them not much healthier than your typical tortilla chip.”
Spending more time in the kitchen can help you shed belly fat, as long as you’re cooking with the right foods, according to one 2017 study. After analyzing data from more than 11,000 men and women, UK researchers found that people who ate more than five homemade meals per week were 28 percent less likely to have a high body mass index, and 24 percent less likely to carry too much body fat than those whole only downed three meals at home.
So, obviously, what is going to work for each person is different, and that’s OK. If your weight-loss practices help you identify areas for behavioral change and give you tools on how to make that happen, or just help keep your motivation up or feeling good, great. “But if you are not losing weight, then the tools you are using aren't working for you,” Fear says. “Many people keep doing the same monitoring even though it's actually not helping them. A sense of control and organization are not to be confused with efficacy.” Use this as an opportunity to try something else.
Using a layered approach is another great way to build a good veggie habit. For example, start with a food you already enjoy — say, pasta — and layer some veggies into your bowl. This can help you explore a new food with one you already love eating, and from there, you can try new ways to savor it. Take spinach, for instance. After trying it with pasta, you may want fold it into an omelet or another favorite food, or explore it on its own with different cooking techniques (sautéed or steamed) or different flavor additions (garlic or golden raisins). The possibilities are limitless!
If you dislike cooking, abhor making food choices, or simply want low-calorie options shipped to your door, Nutrisystem might slot into your life. But it can get expensive, and food selection and flavor are hit-or-miss. Mostly miss. “It’s enough substance to call it a meal, but the texture of every ingredient was lacking,” our tester reported without enthusiasm.
If you want to lose weight, you’d better avoid special “low-carb” products that are full of carbs. This should be obvious, but creative marketers are doing all they can to fool you (and get your money). They will tell you that you can eat cookies, pasta, ice cream, bread and plenty of chocolate on a low-carb diet, as long as you buy their brand. They’re full of carbohydrates. Don’t be fooled.

Dairy products contain varying amounts of lactose (milk sugar), which slows down weight loss. What’s more, part of the protein in milk generates a significant insulin response, which can have the same effect. Consequently, cutting back on dairy products may accelerate weight loss. This applies especially to dairy products typically lacking in fat, such as regular milk and various yogurts, but be careful with full-fat dairy such as cream and cheese all the same. And don’t forget whey protein powder, which is pure milk protein.
Also, while your menstrual cycle may not affect weight gain or loss, losing or gaining weight can affect your menstrual cycle. Women who lose too much weight or lose weight too quickly may stop having a period, or have irregular periods. Women who have obesity may also have irregular periods. A regular period is a sign of good health. Reaching a healthy weight can help women who have irregular periods to have cycles that are more regular. Learn more in our Menstrual Cycle section.

Sure, you can lose weight quickly. There are plenty of fad diets that work to shed pounds rapidly -- while leaving you feeling hungry and deprived. But what good is losing weight only to regain it? To keep pounds off permanently, it's best to lose weight slowly. And many experts say you can do that without going on a "diet." Instead, the key is making simple tweaks to your lifestyle.

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