The 4 Most Important Things You Need to Know About Flexible Dieting

This article is re-posted from Evidence Magazine 

Letting yourself enjoy your favorite foods in moderation, like my Boston Cream Pie Cupcakes, will help you reach your long-term fat loss goals.

You’re willing to suffer.

You want to be lean yesterday, and you’re willing to do whatever it takes to get there.

You cut calories, eliminate as many foods as you can, and deal with being miserable because you know it will pay off.

It will, in the short-term.

It won’t, in the long-term.

When you can’t maintain your diet any longer, and you don’t know how to stay lean without it, you’ll lose all of your hard earned progress.

The truth is that you’ll lose more fat, faster, with less trouble, and keep it off in the long-run, by giving yourself a break.

In this article, you’ll learn the general principles behind a concept called “flexible dieting.” As you’ll see, this is a system that helps you direct your dieting efforts in a way that gives you the results you want, without driving you insane.

This article is mostly about fat loss, but the same principles are just as important for muscle gain, weight maintenance, and general health.

A Simple Introduction to Flexible Dieting

Be less strict about your diet.

That’s the essence of flexible dieting.

Instead of forcing yourself to follow a set of rigid, unsustainable rules to lose fat or stay healthy, you take a more relaxed and long-term perspective on your diet.

The term “flexible dieting” has gotten popular for a reason — it works. What’s confusing, however, is that there isn’t an objective definition of flexible dieting. It means different things depending on who you ask. You’re about to learn the fundamental concepts behind flexible dieting, why it works, and how to start using it.

Lyle McDonald was probably the first person to popularize the concept of flexible dieting. In fact, he wrote the book on the topic in 2005 called A Guide to Flexible Dieting.

McDonald lays out what he believes are the two main reasons dieters fail:

  1. Being too absolute and expecting perfection.
  2. Focusing only on the short-term.

Flexible dieting is basically the opposite — not being as absolute and focusing on the long-term as well as the short-term.

Let’s take a closer look at what flexible dieting is and isn’t.

The 4 Essential Elements of Flexible Dieting

Flexible dieting has several different interpretations, but we’re going to define it with the following four criteria:

  1. Modifying your diet based on your preferences, goals, and tolerances.
  2. Letting yourself enjoy your favorite foods in moderation without feeling guilty or deprived.
  3. Staying calm and sticking to your diet if you do overeat, or have something that’s not “on” your diet.
  4. Focusing just as much on maintaining fat loss as on achieving it.

Let’s take a closer look at each of these principles and why they work.

1/. Modify your diet based on your preferences, goals, and tolerances.

You should eat foods that you enjoy.

You should enjoy both “healthy” and “unhealthy” foods.

There are no specific foods you need to eat to be healthy or lose fat. Food isn’t “bad,” “good,” “healthy,” “unhealthy,” “super,” or anything else. It’s just food. You should eat a well rounded overall healthy diet, but you should enjoy all of the foods you eat within that diet.

Your diet should also support your goals. If you’re trying to lose fat, you need to eat fewer calories. If you’re trying to gain weight, you need to eat more calories. If you’re training hard, you might want to eat more carbohydrate or protein.

It’s fine to place restrictions on yourself to make it easier to reach your goals. If you enjoy higher fat foods and it’s easier for you to control your calorie intake by eating a low-carb diet, then do it. If eating “paleo” — avoiding grains, legumes, dairy (and other stuff, depending on who you ask) helps you eat less, then go for it. Just remember why you’re eating that way. Your diet isn’t magical; it’s just easier for you to follow.

You should also consider any medical reasons for avoiding certain foods. If you’re less insulin sensitive, you may need to eat fewer carbs. If you have celiac disease, you can’t eat gluten.

Base your diet on personal preference first. Modify your diet to suit your goals second. Then take into account any potential restrictions you might need to place on yourself.

Most popular diets do the exact opposite of this approach. They tell you to avoid certain foods or foods groups based on pseudoscience and anecdote, regardless of your goals.

Flexible dieting is the opposite. You get to decide what you do and don’t eat to reach your goals.

2/. Let yourself enjoy your favorite foods without feeling guilty or deprived.

Unless you have a specific medical condition like celiac disease, there is no reason you need to avoid any food forever. There’s also no reason you need to eat the exact same diet every single day for the rest of your life.

You should let yourself enjoy your favorite foods throughout your diet. When you do, you shouldn’t have to feel guilty.

Some people prefer to take a binary approach to dieting. They eliminate all desserts, sugar, added fat, or certain food groups. There’s nothing wrong with this approach as long as you let yourself enjoy these foods later, in moderation, when you’ve reached your goal.

Most people don’t. They deprive themselves of their favorite foods and end up miserable or, more likely, bingeing on them later. This also usually happensbefore they’ve gotten as lean as they want to be, which makes them even more depressed.

With flexible dieting, you let yourself enjoy your favorite foods, whether it’s cake, brownies, bagels, ice cream, cereal, pizza, pasta, french fries, or steak throughout your diet. You don’t damn up your cravings and let them break through later on when you can’t control them.

In most cases, it’s best that your fat loss diet be essentially the same as your regular diet.

3/. Stay calm and stick to your diet if you do overeat or have something that’s not “on” your diet.

Whether accidentally or intentionally, you’re going to eat more calories than you mean to, or you’re going to eat a food that isn’t “on” your diet.

It’s going to happen. The only thing that separates successful dieters from unsuccessful ones is how they react.

If you’ve been depriving yourself of your favorite foods and forcing yourself to stick to a diet you don’t enjoy, you won’t react well. You’ll either hate yourself for failing to stick to your diet, or binge, and then hate yourself even more.

When you break the rigid and unrealistic rules you’ve set for yourself, you feel like there’s no point in trying. Five Oreos turns into an entire box. An extra scoop of ice cream turns into the whole carton.

On the other hand, a flexible dieter stays calm in these situations.

Flexible dieters put the magnitude of their mistake into perspective. They realize that one scoop of ice cream or an Oreo has literally delayed their progress by about 100 calories — the equivalent of maybe an hour or two.

Flexible dieters don’t feel like they’ve failed, cheated themselves, or broken any rules, because they set reasonable expectations from the beginning. Theyexpected to overeat on some days and to eat some foods that weren’t “on” their diets. It’s all just part of the plan.

Rigid dieters do not. They expect to eat exactly the right foods in exactly the right amounts every day, and when they can’t, they give up or hate themselves for not reaching their unreachable expectations.

4/. Focus just as much on maintaining fat loss as on achieving it.

If you’re a rigid dieter, you think in the short-term for two reasons:

  1. You want results as fast as possible, so you set up a diet you hate because you rationalize that it won’t last that long.
  2. After you’ve set up a diet you don’t like, you become even more focused on the short-term because that’s the only way you can make your diet bearable.

When you don’t enjoy your diet and set impossible standards, the only way to have any hope is to focus on the short-term. You adopt an “it can all be over soon” mentality.

In some cases you might reach your goal. However, losing fat isn’t the hard part. It’s maintaining fat loss that’s really hard.

This is where rigid dieting almost always fails.

The behaviors that help you lose fat are the same ones that will help you stay lean. If you can’t maintain the diet and exercise habits that you used to lose fat, you probably won’t be able to stay lean in the long-term.

For instance, studies have consistently shown that meal replacements and weight loss shakes help people lose a lot of weight.(1-5) It helps them control their portion sizes and calorie intake. The problem is that these people never learn to control calories without the shakes and meal replacements. They never learn how to maintain weight loss with sustainable and enjoyable behaviors. That’s why longer studies have generally shown that meal replacement diets are not great at helping people maintain much weight loss.(6)

With flexible dieting, your fat loss diet is almost identical to your habitual diet. There’s no abrupt transition from your fat loss diet to your regular diet, because the only real difference is your calorie and macronutrient intake.

Instead of seeing your diet as an obstacle that you can forget about once you’ve gotten lean, think of it as a long-term transition to healthier behaviors that you’ll use to stay lean for the rest of your life.

Eat a Diet You Can Maintain

That’s essentially what it means to be a flexible dieter.

You want to get lean as fast as possible, so you rush. You put up with cravings, hunger, lethargy, and social isolation because you’re willing to suffer. You set rigid, impossible, miserable standards that you can’t achieve.

You either give up before, soon after, or long after reaching your goal, because being lean wasn’t worth the trouble anymore.

Flexible dieting is about finding a diet that works for you, and deviating from that diet in a way that doesn’t impede your long-term progress.

How has rigid dieting helped or hurt your efforts to get lean? How do you eat a structured diet to lose fat while maintaining your sanity, social life, and happiness?

Share your thoughts in the comments section below.


1. Davis LM, Coleman C, Kiel J, et al. Efficacy of a meal replacement diet plan compared to a food-based diet plan after a period of weight loss and weight maintenance: a randomized controlled trial. Nutr J. 2010;9:11. doi:10.1186/1475-2891-9-11.

2. Cheskin LJ, Mitchell AM, Jhaveri AD, et al. Efficacy of meal replacements versus a standard food-based diet for weight loss in type 2 diabetes: a controlled clinical trial. Diabetes Educ. 2008;34(1):118–127. doi:10.1177/0145721707312463.

3. Heymsfield SB, van Mierlo CAJ, van der Knaap HCM, Heo M, Frier HI. Weight management using a meal replacement strategy: meta and pooling analysis from six studies. International Journal of Obesity (2005). 2003;27(5):537–549.

4. Ditschuneit HH, Flechtner-Mors M. Value of structured meals for weight management: risk factors and long-term weight maintenance. Obes Res. 2001;9 Suppl 4:284S–289S. doi:10.1038/oby.2001.132.

5. Shikany JM, Thomas AS, Beasley TM, Lewis CE, Allison DB. Randomized controlled trial of the Medifast 5 & 1 Plan for weight loss. International Journal of Obesity (2005). 2013. doi:10.1038/ijo.2013.43.

6. Lopez Barron G, Bacardi Gascon M, De Lira Garcia C, Jimenez Cruz A. [Meal replacement efficacy on long-term weight loss: a systematic review].Nutr Hosp. 2011;26(6):1260–1265. doi:10.1590/S0212-16112011000600011.

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