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10 Crash Diets Nutrition Experts Secretly Use

Crash diets aren't a great strategy for long-term weight loss or health, but when it's class reunion time, here's how the pros lose weight fast.

Woman is injecting hormones by single use syringe pen with dose. Ectrocorporal conception, Diabetes concept.Creative Director/Shutterstock

“I inject myself with pregnancy hormones”

“When I want to lose weight quickly, I do the hCG diet, using daily hormone shots, along with a strict diet. HCG stands for Human Chorionic Gonadotropin and is a hormone that helps to shed the fat that is stored in our bodies. Normally, it’s associated with pregnancy as it pulls out stored fat, in preparation to give it to the baby. But if you’re not pregnant, you get rid of the extra fat when you urinate. The diet that goes along with this medication is very low-calorie—between 500 and 800 calories per day—but it is made up of purely clean and healthy foods. The hormone plus the diet is what causes rapid weight loss. I average about 5 pounds per week.” —Shannon Cook, nurse practitioner at Slimmer Solutions.

Fish OilSOMMAI/Shutterstock

“I drink shots… of fish oil”

“To lose weight fast, I take a mega dose of fish oil. Usually people take the recommended dose, as stated on the product label, but I’ve found that higher doses rapidly shift my body into a fat-burning machine. To do this, I buy a lemon or orange-flavored liquid fish oil, otherwise I’d be taking fistfuls of capsules. I start with the recommended dose per day or slightly higher and ramp up the amount until I start to experience loose stools. This will occur because fish oil is fat, after all. Plus, the extra healthy fats help keep me full and prevent sugar cravings, making it easier to limit calories. I keep the dose as high as I can but just below whatever level causes the diarrhea. I only do this for a couple of weeks at a time, but I’ll see a rapid drop in my weight during that time. It’s important to note that since fish oils thin the blood, you should always consult your doctor first, especially if you are on blood thinners or any other medications.” —RJ Kayser, nutrition coach for Olorin Nutrition. Don’t miss the 11 reasons apple cider vinegar weight loss works.

Vertical overhead perspective of three oiled brown uncooked baked russet potatoes sprinkled with kosher salt flakes arranged in row on aluminum foil lined metal quarter sheet pan for oven bakingPeterVandenbelt/Shutterstock

“I eat potatoes, and only potatoes, for days”

“The potato hack is a proven way to lose weight quickly, especially if you are weight-loss resistant. This is where you eat only cooked and cooled potatoes for three to five days of the week. Eat a normal healthy diet for the remainder of the week and repeat until your weight loss goal is met. The rules are simple: Eat as many potatoes as you want, but no other food, and only drink water or black coffee or tea. No toppings like butter or sour cream and even seasoning, like salt, is discouraged but not totally off-limits. If needed you may use a little sea salt, paprika, or pepper. The hack works because when potatoes are cooked and cooled it creates ‘resistant starch,’ which is not digested and absorbed by the GI tract. The other reason this works: When people are limited to one food choice, especially if it’s not highly palatable, they tend to eat less.” —Denny Hemingson, functional diagnostic nutrition practitioner. Try these 12 tricks to make your guilty pleasure foods healthier.

Glass with protein shake and powder in scoop on wooden tableAfrica Studio/Shutterstock

“I drink meal replacement shakes”

“Replacing snacks and even some meals with meal replacement shakes is one of the things I do when I’m trying to lose weight quickly. Since I’m replacing a meal, I make sure the shake is made from whole food ingredients and that it is well rounded and intended to replace a meal. It’s really easy—all I do is combine the powder with water and drink it. It helps me consume fewer calories overall without starving myself of all the necessary nutrients. This also works because it eliminates bad foods that cause bloating and inflammation. Plus it helps my body release excess waste stored in the bowels.” —Morgan Sheets, certified wellness coach. (Psst…here’s how to lose weight—without a lick of exercise.)

healthy vegan lunch bowl. Avocado, quinoa, tomato, cucumber, red cabbage, green peas and radish vegetables salad. Top viewAnna Shepulova/Shutterstock

“I cut out all animal products”

“I’ve learned that when it comes to weight loss, diet works much faster than exercise. I adopt a strict whole-food, plant-based diet. That means fruit, veggies, grains, legumes, and that’s it. I dropped 15 pounds in the first ten days on a plant-based diet. All the fiber keeps me full, plus you get an extra calorie burn by eating plant foods that can last up to four hours after a meal. This raises my metabolism, and the extra energy makes me want to move my body more. I stuck to it and lost another 55 pounds over the next nine months. I was amazed at how easy it was. Dropping the meaty, cheesy diet along with all processed foods just works and it works fast.” —Scott Putnam, plant-based nutrition expert and health coach at Whole Living Nutrition, llc. Here are 14 things you need to know about losing weight on a vegan diet.


Glasses of fresh juice on gray stone table. Food backgroundLeszek Czerwonka/Shutterstock

“I drink smoothies and spend hours in the sauna”

“Normally I manage my weight by eating a healthy diet and exercising, but if I want to lose weight fast, I literally eat smoothies three times a day for ten days. The key is to make them with whole foods and no added sugars. This can have a ‘cleansing’ effect on the system. If I feel really hungry, I’ll add in a couple of boiled eggs a day. Lastly, no alcohol! Another way I speed up weight loss is to sit in a sauna for one hour a day; dropping the water weight that adds to the pounds lost.” —Priya Khorana, EdD, exercise physiologist and nutritionist.

Healthy green meal prep containers with chicken, rice, avocado and vegetables overhead shotElena Veselova/Shutterstock

“I go super low-fat”

“I don’t recommend a rapid weight-loss approach in general—it’s unsustainable and can lead to yo-yo dieting—but for the rare occasions when I or a client wants to lose a few pounds fast I have found the best approach is to reduce fat intake to 10 to 12 percent of total calories per day. I recommend reducing fat instead of carbohydrates because carbs are your brain and muscles’ primary energy source. Not only is drastically cutting carbohydrates unsustainable (they’re everywhere!) but doing so negatively impacts energy, exercise performance, recovery, and appetite management. Additionally, by cutting fat you can create a greater calorie deficit because fat provides more than twice as many calories per gram compared to carbohydrates. This allows you to still eat a lot of food but for fewer calories. Make sure to eat lots of protein during this time to preserve muscle maintenance and to help with appetite management.” —Paul Salter RD, Nutrition Editor and the founder of Fit In Your Dress. If you’re planning to try this strategy, try these 25 kitchen shortcuts you’ll wish you knew sooner.

High Angle View Of A Person Hand Filling Meal Plan In Notebook At Wooden DeskAndrey_Popov/Shutterstock

“I do the 5:2 diet”

“Whenever I have a big speaking event coming up, where I know I’ll be on camera, I use calorie cycling. It’s one of the easiest strategies to drop weight fast. All I do is pick one or two days each week to restrict my eating to 500 to 750 calories, primarily from protein and vegetables. Then I eat normally the rest of the week. This is an easy way to shed a few quick pounds and move some water weight as well, making it a good strategy for an upcoming vacation or wedding.” —Darin Hulslander, personal trainer and nutritionist at This Is PerformanceFind out the 37 secrets nutritionists won’t tell you for free.

fir tree essential oil on dark background - beauty treatmentmatka_Wariatka/Shutterstock

“I put pine needles on my food”

“One of my favorite weight-loss hacks is delicious pine oil. Not only is pine oil easy to make (all you need are pine needles from your own trees!), it’s also one of the most natural and organic system stimulants and metabolic boosters you can find, ultimately helping weight loss. Once ingested, pine oil works as an antimicrobial, flushing out harmful bacteria in your system and preventing infections as well as parasites. Because of this property you can use it as a marinade, a salad dressing, or as a kitchen cleaner and sanitizer.” —Caleb Backe, health and wellness expert for Maple Holistics.

Eight hour feeding window concept or breakfast time with clock on plate and knife and fork on wooden table, overhead viewdesignelements/Shutterstock

“I just don’t eat—at certain times”

“I normally eat a whole-foods, plant-based diet, but when I want to lose a little extra weight, I practice intermittent fasting. Basically this means limiting when I eat to a very limited window of time. The rest of the time I don’t eat any food and only drink water. I like to make sure I am fasting for at least 14 hours, as this allows my digestive system to rest. People who do intermittent fasting typically use fasting windows ranging between 16 and 36 hours. If I really want to lose weight, I also cut out all sugar.” —Evelisse Capo, PharmD, nutrition coach and cooking instructor with The Food PharmacyIt’s not as bonkers as it sounds—check out the proven benefits of intermittent fasting.

Next, find out the 50 things doctors need you to know about weight loss.

Charlotte Hilton Andersen
Charlotte Hilton Andersen has been covering health and fitness for many major outlets, both in print and online, for 13 years. She's the author of two books, co-host of the Self Help Obsession podcast, and does freelance editing and ghostwriting. She teaches fitness classes in her spare time. She lives in Denver with her husband, four children, and three pets.