Venture into any fitness center, yoga studio, or CrossFit box in America, and you’re bound to hear a different buzzword each month about the hottest new way to diet, much of which is bizarre, and some downright dangerous. In fact, there’s no shortage of advice on what to eat and what to avoid, which can make it challenging to navigate the seemingly endless opinions on which approach is best. With so much conflicting advice, it’s no wonder many women begin feeling discouraged before they have even started.
So what is the best way to eat if you want to get (and stay) slim in a healthy way? The key is to find balance. It’s never a good idea to completely eliminate any of the macronutrients (protein, carbs, and fat) from your diet. By ditching entire food groups, you’re prone to serious nutritional shortfalls. Carbs, for instance, fuel your brain and muscles, both of which primarily use glucose (a simpler form of carbohydrate) as their energy source. Fat, another major fuel source for your body, has multiple functions, such as helping your body use fat-soluble vitamins, regulating inflammatory processes and responses, and helping hormone production.
By smartly manipulating your macronutrient intake, you can coax your body into burning calories and body fat more efficiently. We’ve got the lowdown on three such popular approaches to weight loss: carb backloading, If It Fits Your Macros (IIFYM), and carb cycling. Read on to see which one best suits your lifestyle and can help you reach your better-body goals.
2 of 5
Christopher Stevenson/Corbis & JJD/Cultura/Corbis
Developed by John Kiefer, a physicist turned nutritionist, the carb backloading method makes dieting dead easy. It entails consuming proteins and fats throughout the day, then “carbing up” later in the day, often with fast-digesting carb sources such as cake (yes, cake!) in order to blast fat. The premise: When the body has few carbs throughout the day, the amount of glucose in the bloodstream is limited, so your body will draw on its fat stores for fuel.
At first glance, it seems a little reminiscent of the Hollywood Cookie Diet—you know, the one in which you eat four cookies per day and only one healthy meal? (Yeah, we must have missed that one, too!) But rather than starve your body of all nutrients except sugar for hours on end, the carb backloading approach takes advantage of the natural daily fluctuations in insulin sensitivity.
Research shows that insulin sensitivity is higher in the morning than in the evening, which means both muscle and fat cells are more receptive to carbs (glucose) earlier in the day. When you eat any carbs, either sugar or starch, your pancreas releases insulin to help your body utilize them. If you’ve just finished a workout, the insulin will help quickly shuttle the carbs plus the other nutrients you consume to your muscles to help repair and rebuild the tissue. Earlier in the day, the insulin will typically cause those carbs to become stored as fat. But if you steer clear of carbs as a fuel source throughout most of the day, blood-sugar levels remain low, so your body will burn more fat for fuel. Kiefer asserts that manipulating this effect is the key to burning fat while also creating an environment that’s conducive to muscle growth.
How it works: Upon waking in the morning, your body is in a powerful fat-burning mode. Eating can cause you to switch gears into a fat-gaining mode, proponents of the plan maintain. So skip this meal, fasting for at least two hours in the a.m. Contrary to popular belief, eating breakfast every morning does not give you a fat-burning edge. In fact, researchers from the University of Bath in the U.K. found no increase in resting metabolic rates of breakfast eaters compared with those of people who fasted every morning over a period of six weeks. And skipping breakfast didn’t prompt gorging later in the day, either.
Starting midmorning, Kiefer says to eat lightly, consuming only protein and fats for the majority of the day. Because you’re eating little to no carbs, there will not be much glucose in the bloodstream, so your body will draw on its fat stores for fuel. Then, after your evening workout (5 p.m. or later), begin consuming carbs in a post-workout meal; continue loading up on carbs throughout the evening. Choose fast-digesting carbs such as white rice, white potatoes, yams, sweet potatoes, and corn. Even sugar-laden junk foods such as cookies and ice cream are OK in moderation, say some fans of the diet.
“With weight training, muscle cells release glycogen [the stored form of glucose] for fuel,” explains Sara Fennell, a contest-prep coach and IFBB figure pro. “This causes glucose receptors to rise to the surface of the cell’s membrane and become very sensitive, looking for, and wanting, more glucose, so you can consume carbs without gaining fat.” Fennell follows up her workouts with a piece of cake and says that carb backloading was key to her success at the 2014 IFBB North American Championships, in which she earned her pro card—and achieved her leanest physique yet.
Keys to Carb Back Loading
Protein: 0.8-1.0 gram per pound of body weight
Carbs: (on training days): 50-150 grams
For maximum fat loss, keep carb intake closer to 1 gram per pound of body weight
Carbs (on nontraining days): 30 grams or less daily
It sounds too good to be true: Eat what you want, when you want, and still lose weight. But according to the If It Fits Your Macros (IIFYM) diet, the key to weight loss is not about the types of foods you consume but rather the amount of calories you are consuming—and burning off. It’s based on the calories-in-versus-calories-out principle, which Joe Klemczewski, Ph.D., president of thedietdoc.com, says is the most important variable in weight loss.
A calorie is a calorie&mdas; whether the calorie comes from an apple or a piece of chocolate cake, it is essentially equal, according to this nutrition program. “If you put a lower-octane fuel in your car or the highest, a gallon of gas is still a gallon of gas,” Klemczewski explains. “There are other variables you should consider when dieting—glycemic index, ratios of macronutrients, meal formatting, and timing—but nothing comes close to quantity [of calories] as the hinge point of success.” The foundation of IIFYM successful weight loss is based on a simple equation: You must burn more calories than you consume.
Calories fuel your every action, from fidgeting at your desk to squatting in the gym. While the IIFYM approach sounds simple, flexible, and relatively easy to follow, Klemczewski says there are some cautions. Technically, you can hit your daily target eating nothing but Twinkies, but you’ll optimize fat loss and lean muscle gains by fueling up with the right foods—a balanced intake of protein, (complex) carbs, and healthy fats. “Eating a bunch of junk just because ‘it fits your macros’ misses the entire point of flexible dieting,” Klemczewski says. “Flexible dieting is based on research that shows meal timing, spacing, and even food sources have little impact on results compared with overall calorie and macronutrient intake levels.”
Still, Klemczewski says there are some “gray area” foods that are OK to consume in small amounts and at specific times. One such food is sugar, which is particularly beneficial pre- and post-workout. The IIFYM approach promotes controlled intake in order to prevent uncontrolled binge eating, a common pitfall for most dieters. “The research shows that people are far more successful long term when they don’t restrict themselves from entire food categories or if they allow for periodic indulgences through the dieting process,” Klemczewski explains.
How it works: To get the most out of IIFYM, maintain a balanced, healthy diet. To properly count calories, you’ll first have to calculate your basal metabolic rate (BMR). This is the amount of energy you expend each day while at rest. You can calculate your BMR online at websites such as iifym.com, or you can do the math yourself. The BMR formula for women is 655.1 + (4.35 x your weight in pounds) + (4.7 x height in inches) – (4.7 x age in years). Combine your BMR with the number of calories you burn from exercise to get your average total daily energy expenditure (TDEE). This is the number of calories you need each day to maintain your current weight. If your goal is to lose weight, aim to consume approximately 15% fewer calories from your TDEE. (You can also calculate your TDEE at iifym.com.)
Keys to IIFYM
Protein: 1.0 gram per pound of body weight
Fats: 0.35 grams per pound of body weight
Fiber: 20-25 grams
Carbs: all remaining calories will come from carb intake.
4 of 5
Christopher Stevenson/Corbis & JJD/Cultura/Corbis
If you want to lose weight, following a low-carb diet can yield better results than following a low-fat diet, according to numerous research studies. One recent study from the Annals of Internal Medicine found subjects who followed a low-carb diet lost more weight and body fat compared with those who followed a low-fat plan. Carb cycling is essentially a low-carb diet with intermittent higher-carb days (called refeeds) to help boost fat burning and build muscle and allow for better recovery.
“The idea behind carb cycling is to use fat as the primary fuel source on lower-carb days, which in turn promotes fat loss,”e; says Linda Stephens, a nutritionist and IFBB figure pro. “On higher-carb days you replenish muscle glycogen stores, which fuels your muscles for tougher workouts.” Giving your body an excess of carbs on high-carb days also promotes a favorable environment for maintaining (and building) muscle. Stephens says the brief, periodic carb (and calorie) surpluses after a period of low-carb intake give your metabolism a boost, which means you’ll burn more fat.
How it works: While there are varying approaches to carb cycling, the most common is a three- to four-day period in which you consume fewer carbs, followed by a day of high-carb intake, a cycle that you then repeat. “You can always tweak your macronutrient intake based on how you feel and look and your activity level,” Stephens says. Fat intake is inversely related to the carbs you consume, so on days when carbs are high, your fat will be low, and vice versa. Protein intake will remain fairly steady throughout.
Keys to Carb Cycling
On low-carb days:
Carbs: 0.2-0.5 grams per pound of body weight
Protein: 1.2 grams per pound of body weight
Fats: 0.5 grams per pound of body weight
On high-carb days:
Carbs: 1.0-1.5 grams per pound of body weight
Protein: 1.4 grams per pound of body weight
Fats: 0.2-0.3 grams per pound of body weight.
5 of 5
Our 15 Favorite Fat-Burning Foods
Christopher Stevenson/Corbis & JJD/Cultura/Corbis
No matter which diet plan you follow, these foods can help you slim down while fueling you for exercise or recovery: