First, what is it?

“Diet stacking” is the practice of following two or more dietary strategies at the same time—sometimes for valid medical, social, or religious reasons, but increasingly by layering restrictions (for example, gluten-free plus low-fat plus “clean eating”) without clear benefit or a plan to stop ineffective diets.

So for example:

• If you have celiac disease and are trying to put on weight, you might aim for calorie-heavy foods, but skip those that contain gluten (so: many grains, which also means most bread and most pasta, i.e. foods that many people prioritize when trying to put on weight)
• If you are Muslim and are for your own reasons vegan, then well, a vegan diet is already halal by default (assuming you also don’t drink alcohol), but this combination means you’ll probably be eating the least of anyone at Eid al-Adha.
• If you are diabetic and are trying to lose weight with a calorie-controlled diet, then you may find a restrictive diet plan troublesome when you urgently need to fix a hypo at three in the morning.

…and so on.

Which is not to say that combinations of dietary approaches can’t be healthily done. They absolutely can. But one has to be mindful about it, and trouble-shoot likely problems in advance.

In order to do that, it’s necessary to…

Know the risks

In few words, the primary problem is that stacking restrictions can worsen symptoms (where applicable, or give you symptoms otherwise!), lower overall diet quality, and increase the risk of disordered eating, with potential long-term consequences including the usual culprits such as heart disease, type 2 diabetes, other metabolic problems, various cancers, weakened immunity, osteoporosis, fatigue, and poorer mental health. Which latter is not surprising, given the stack of adverse physical health conditions we just mentioned. It’s hard to stay in good mental health when facing those things!

Indeed, a recent study concluded:

❝In conclusion, diet stacking is common, and requires awareness and often multidisciplinary management to ensure it is implemented safely❞

~ Dr. Sarah Melton

Read in full: Diet Stacking—An Expanding Challenge for Gastroenterologists and Dietitians in Managing Chronic Gastrointestinal Disorders

And yes, Dr. Melton does put the emphasis on gastroenterology, saying:

❝For gastroenterologists, awareness of current dietary practices of their patients prior to advising dietary therapy is warranted and, in those who are diet stacking, risk assessment is essential. Validated screening tools to evaluate risks, particularly of disordered eating, are limited.

The management of those who currently or are at risk of diet stacking is best directed toward gastrointestinal dietitians who offer time, appropriate skills for assessment, and the delivery of pragmatic patient education to safely implement appropriate dietary interventions, and assess for the need for engaging psychological primary management or co-management.❞

~ Ibid.

Manage the risks (actively!)

It is easy, when jumping on a dietary bandwagon that promises the most glowing health you’ve ever enjoyed (and maybe even has a wealth of science to back up those claims), to disregard any potential criticisms of those very same dietary approaches.

Instead, do the opposite. Examine the criticisms, critically.

By this we mean: find out what the most common criticisms of a diet are, do the research to find out whether those criticisms are valid, and manage the risks. This goes for each individual dietary approach, of course, but there’s a good chance you’ll have to use your own head a little when it comes to combining dietary approaches.

For example, a low-FODMAP diet may be medically indicated to manage the symptoms of IBS. If you’re also trying to get enough fiber to keep your blood pressure down, when fiber comes from plants and so many plants are high in FODMAPs, while still getting good, balanced nutrition?

We covered this one, actually: Fruit, Fiber, & Leafy Greens… On A Low-FODMAP Diet!

Or if you’re diabetic and trying to do almost anything else with your diet besides “manage your blood sugars”, then then you will almost always have the added challenge of “…and do so without going hypo/hyper”. So in that case, you’re going to have to ask: “how can I eat in this certain way, while also being sure that I can always correct a hypo?”

We say “correct a hypo”, because the method of correcting hyperglycemia will never be “eat more food right now”.

One obvious approach is flexibility. You can be dietetic and have your low-carb diet if you like, but just give yourself permission to ignore the low-carb restrictions completely if you’re about to pass out from hypoglycemia.

See also: What Flexible Dieting Really Means (And What It Doesn’t)

Another approach to many dietary combinations is supplementation. Even the most rigorous vegan diet can be supplemented, if you like. Sure, you could get your vitamins B12, D, and K from yeast, mushrooms, and kiwi fruit, but what if you don’t love those? Supplements to the rescue. Of course, that’s one diet not several, but the solution can be the same for inconvenient combinations too.

Ask yourself one question

Do I feel lu—

No wait, that’s not it.

The question is: how will I get my nutrients?

And by nutrients we mean at the very least:

• sufficient calories, because you cannot run a high-end machine without enough fuel!
  • See: Are You A Calorie-Burning Machine?
• an adequate set of macros (carbs, fiber, protein, fats)
  • See also: What Macronutrient Balance Is Right For You?, of which…
    • Should You Go Light Or Heavy On Carbs?
    • What Do The Different Kinds Of Fiber Do? 30 Foods That Rank Highest
    • Protein: How Much Do We Need, Really?, of which…
      • Why You Can’t Skimp On Amino Acids
    • Saturated Fat: What’s The Truth?
    • What Omega-3 Fatty Acids Really Do For Us
• a full complement of vitamins (they are called that for a reason; you will die without them)
  • Being aware of such things as:
    • Which B Vitamins? It Makes A Difference
    • Are Your Vitamin D Supplements Working? Probably Not (Here’s Why & How To Fix It)
    • Vitamin K2 And The Calcium Paradox
• sufficient intake of minerals (or else a lot of things start breaking down and your body will start cannibalizing itself, e.g. taking phosphorus from your bones and teeth in order to maintain the phospholipid layer of cell membranes)
  • Especially bearing in mind: Which Magnesium? (And: When?) ← around 80% of people in the US do not meet the RDA for magnesium, so make sure that’s not you!

Want to learn more about different dietary approaches?

Check out:

Which Diet? Top Diets Ranked By Experts

Choose wisely!