Updated

While watching fat intake is important for weight loss, eating a low fat diet that includes lots of low-fat food products can actually cause you to gain weight.  Here’s why:

Less fat, more carbs

Fat adds flavor and texture to food, which explains why foods that contain fat are so pleasing. When manufacturers remove fat from a product they often add back flavor using sugar.  The problem is that added sugar means added carbohydrates, so even though a food is billed as low-fat it may well be higher in carbs than the original full-fat version. Excess carbohydrates not burned for energy get stored as fat, resulting in weight gain.

Low fat foods leave you hungry

Fat digests slowly and releases the hormone cholecystokinin, which promotes fullness and satiety.  Foods containing little to no fat digest quickly, leaving you hungry again even though  you’ve just eaten.  Also, without fat to slow digestion blood glucose levels spike and then drop, prompting sugar cravings that can lead to overeating.

You’ll be tempted to eat more

Researchers at the Cornell University Food and Brand Lab found that people who follow a low-fat diet consume about 28 percent more calories. They found that low-fat dieters ate more, believing their low-fat choices had about 40 percent fewer calories when in fact they were only saving about 11 calories per serving.

While a diet that’s high in fat can contribute to serious health issues including heart disease and certain cancers, keep in mind that our body still needs fat for vital functions such as vitamin and mineral transport, nutrient absorption, nerve transmission, and for healthy cells. Rather than eliminate fat from your diet, focus instead on avoiding unhealthy fats while consuming healthier fats.

Most of the fat you eat should be unsaturated, such as monounsaturated fats, which help raise good HDL cholesterol, lower bad LDL cholesterol, and protect against plaque buildup in your arteries. Good sources of monounsaturated fat include: olive oil and olives, canola oil, almonds, cashews, peanuts, peanut butter, sesame seeds, and avocados.

Additionally, polyunsaturated fats are helpful in lowering bad LDL cholesterol and these fats contain essential omega-3 fatty acids that boost brain function, help strengthen your immune system and even improve mood. Most of the polys you eat should be omega-3s, found mainly in wild-caught fish such as salmon, mackerel, and herring, as well as canola oil, flaxseed, walnuts, and tofu. Omega-6 fatty- acids in small amounts help promote skin and eye health, and you’ll find them in corn and safflower oil, corn-fed chicken and beef, and farmed fish.

For delicious high fiber meal plans, recipes and tips on healthy eating, drinking and losing weight, check out my latest book, The Miracle Carb Diet: Make Calories and Fat Disappear – with Fiber!

Tanya Zuckerbrot MS, RD, is a registered dietitian in New York City and the author of two bestselling diet books:  The Miracle Carb Diet: Make Calories and Fat Disappear – with fiber and The F-Factor Diet. Follow Tanya on Facebook, Twitter and LinkedIn, and subscribe to her free weekly weight loss newsletter