What is The Best Diet?

I’m going to wander into the realm of dogmatic nutrition for a moment and discuss some things I’ve observed in over a decade of working with nutrition clients in multiple specialties.

Everyone in the fitness and nutrition industry seems to have their favorite diet or nutrition style/fad/philosophy that they think is just the best. And they’ll tell you all about it, sell you their stuff, and even argue all day online by Pubmed-ing the shit out of you if you disagree.

If you’re one of those PubMed warriors, this post may not be what you’re looking for.

I’m going to talk about observations and experience, and sure, there’s some decent research out there that can be used to back this up, but in my opinion, studies only go so far as to say ‘here’s what this research that was conducted under imperfect conditions says about humans who are prone to error.’

Now, before you think I’m anti-science, I love science. I use it all the time. I HAVE TO use it in my job, and to back up what I say. However, if you’re someone who actually works with real, live humans, you may notice that what science says should happen, is not always what we see happen.

So what I’m discussing in this post is where science leaves off and real clinical application begins.

If you’re here to learn a little (or a lot) about nutrition, including where research ends and where actual practical application begins, keep reading.

Before I proceed, I want to make it clear that the best diet for YOU may not be the best diet for ME. The best diet for YOU is one you’ll follow.

But for the sake of this post, let’s assume you’ll follow anything, and you’re willing to give something a shot for at least 90 days.

One Size Doesn’t Fit All

Whatever diet worked for you to lose body fat is not guaranteed to be the best diet for everyone else to lose body fat.

Whatever results you got from a diet in a certain amount of time are not guaranteed to be the same results everyone else will see.

Let’s understand those two things first.

Some people thrive on a really high carb intake while others need keto in order to maintain body fat levels or lose body fat.

Some people need to venture into paleo or vegan diets in order to feel their best.

If someone tells you they lost 10 lbs a week on a diet and that you can too, because “science,” they’re missing the forest for the trees.

All diets require consistency. Most diets will work for most people as long as you do it long enough and are 95% compliant with it. So in that context, you can largely pick a diet and follow it and see results.

Where many diets or diet trends fail is they aren’t sustainable long term.

So let’s break down where my observation comes in regarding some trends I see happening and maybe where people are going wrong.

Carbs Absolutely Do Matter

I’ve followed all kinds of carb-level-type diets and largely see about the same results, but with some differences. I could say the same for most of my clients, depending on their compliance to the plan they’re given.

Some people, however, respond very poorly to low- or high-carb diets, depending on their situation. This is influenced by everything from their digestive function, to their thyroid, their reproductive hormones, their sleep, and their stress management practices.

I’m seeing a ton of backlash lately to the keto and low-carb camps that dominated the nutrition information space this past decade. Everyone is on the ‘you can eat a metric ton of carbs every day and nothing will go wrong’ bandwagon.

And that’s fine. I think we need balance in the messaging consumers get.


Some of the pro-carb enthusiasts are getting lost in their attempts to prove a point that ‘carbs don’t make you fat’ that the amount of carbs they are often recommending to their clients are prohibitive to long-term success.

I’m talking somewhere in the neighborhood of 400+ grams/day for a 150-180 lb person. This breaks down to be about 2.6 – 2.2 grams of carb per pound of bodyweight.

Another way to look at that is its 1600+ calories of carbs. The average active person in that weight range is eating between 2200 – 2600 calories, so we’re looking at ~ 60-72% of daily calories coming from carbs, which doesn’t leave much for protein, and even less for fat.

Unless you are an Olympian or a semi-pro level athlete, or perhaps someone that trains at an elite level in a demanding sport (CrossFit, ultra endurance, triathlons), you really don’t need THAT many carbs very often, and when you do, you’re also eating significantly more protein and fat to balance those carbs (so your overall calories are higher, as well).

Why is this a problem?

This is not a long term solution for the vast majority of general population or even fitness enthusiasts.

If you think you’re not just a fitness enthusiast, chances are, you’re wrong. You’re also likely more sedentary than you think you are, too.

Let’s say you diet down, cut a bunch of body fat, achieve a relatively low body fat level and a higher lean body mass.

Great. This is a good thing.

Then your coach/nutritionist wants you to jack the carbs up, keeping protein moderate but fat very low.

Ok, sounds fine…for a short period of time. Like 4-6 weeks tops. This is just refeeding/recomping depleted muscle glycogen and you’re going to feel really great during workouts for a while initially.

But you hit a plateau all of a sudden at some point and start to gain back body fat, retain water, or feel sluggish. Sound familiar?

Adaptive mechanisms in nutrition happen all the time, and they’re biologically necessary. Your body wants to maintain what’s called homeostasis. Homeostasis is just a fancy word for ‘staying the same’ or what I like to call ‘trying not to die.’

A homeostatic mechanism with nutrition or diet would be the body adapting to a lower calorie intake by slowing down metabolism in order to hang onto stored body fat and not ‘starve’ the body of its fat stores in case of a shortage of food, such as humans used to experience before industrialization of our food supply happened.

This is normal and okay.

But, it will also happen when we go the other direction and reverse diet or add back in larger amounts of a macronutrient (carbs, protein, or fat) than we’ve previously had.

Initially, that flood of carbohydrates will simply be stored and burned off during activity and won’t contribute to fat storage in most cases, if its kept in a certain range.

But, the body will quickly realize this abundance of this nutrient is happening for a longer period of time and feedback loops of metabolism will increase the amount of carbohydrate that gets stored as fat compared to what is stored as muscle, because muscles and metabolism have become more efficient at utilizing carbohydrates, so they need fewer of them to perform the same tasks.

Some people take longer to reach this feedback point than others. If you tend toward short adaptation to new diets, then you might be someone that experiences this faster after increasing carbs rather than slower.

Another thing I see too often with these consistently super high carb intakes is sacrificing calories from fat.

All kinds of things go wrong with cutting fats back dramatically.

The two big things I’ve noticed are:

  1. Hormone crashes
  2. Digestive problems.

I’ll get to these in a minute, though.

This same thing eventually happens, too, when we eat high fat and low carb. The body wants balance.

The point is, this strategy is likely not to work for you forever.

Preventing Adaptation

In some settings, adaptation is critical and a good thing. In the corporate world, we consider it necessary for the longevity of an organization.

But when it comes to nutrition and metabolism, things are different.

Much has been written on the subject of preventing metabolic adaptation. I won’t rehash it all here, but just know that this is what people are probably trying to describe when they talk about needing to ‘keep your body guessing’ or some such horseshit.

This concept really does have merit in my opinion. But I wouldn’t say that you’re keeping your metabolism guessing. Your body knows what’s up. Its the result of millions of years of mammalian evolution.

I guarantee you’re not “tricking it” into burning fat, okay?

But what you are doing is avoiding the pitfalls of just one type of metabolic pathway. Your body is being required to perform on both primarily carbs and primarily fat, depending on the day, training volume, and other variables.

In fluctuating your carbohydrate and fat intake over the course of a given week, you can continue to achieve either a caloric deficit or caloric maintenance, while not hitting a plateau from utilizing the exact same energy pathway every single day.

Systems like Carb Nite are based on a similar concept, although the patterns in that particular system utilize both extreme ends of the spectrum of macronutrient distribution (from keto to extremely high carb).

From simply a human evolution perspective, we evolved surviving on a pattern that fluctuated wildly between very high and very low carbs, as well as very high and very low fat (and protein, at times, too).

Our hunter gatherer ancestors experienced these fluctuations regularly and even broadly across the course of seasons, due to variability in obtaining food sources from plants and animals, as well as geographic influence.

I realize that’s observational and speculative as far as this discussion, but its also based on facts about what we know humans have thrived on for the course of our history. We thrive on change.

What Not to Change

Before I get into some more specifics, I want to point out that regularly changing what kind of diet you follow is not likely to produce any better results.

What I’m referring to is the chronic diet-hoppers. Those of you who follow paleo for a few weeks, don’t see drastic results, so you jump to juice fasts, but that doesn’t last long, and then you try vegan but quickly give that up for whatever the next hottest trend is.

This approach has awful results.

Pick ONE type of diet approach and follow it for a minimum of 90 days before deciding it worked or didn’t.

…but within that approach, you need change. I’ll explain what I mean by this.

Nutrient Cycling is Where Its At (IMO)

I won’t use the term carb-cycling here, because its not just carbs that need to fluctuate. You need to change up your fat intake, and at times, protein, as well.

Carb-cycling is built around the premise that you need to change the daily intake level of carbs you eat from sometimes very low to sometimes very high, and everything in between.

Some people cycle carbs over the course of a week, and others cycle them over the course of a month.

Observationally, I see better results for most people when their carbs are cycled over the course of a week, rather than following very low carb for weeks, then switching to very high carb for a couple weeks, and back again.

Beyond cycling carbs, however, I find the best results when fat is also cycled along with carbs, but inversely. This means when carbs are low, fat is higher, and vice versa. But not a whole lot higher fat.

Now, this is where people argue, and things get complicated.

How much is ‘high’ and how much is ‘low’?

What about high volume training and what about powerlifting?

What days of the week? What cycle of the moon? Where can I post this Pubmed link?

So, here we go…

Higher carb days are days in which you are doing a whole lot more lower body resistance work than others.

Even if you’re doing something like CrossFit, where theoretically you’re training many muscle groups, you still tend to have an emphasis on upper or lower body on most days.

Everyone else, you know which days have more lower body resistance emphasis than others.

Moderate carb days are days you train mostly upper body.

And lower carb days are days you don’t train at all, or you do lower volume of anything (can also be active recovery days like playing in the park with your kids, hiking, doing yoga, etc).

The table below can be a rough guide to how carbs might be distributed for you:

Carb Volume% Total Calories
Higher volume45-55%
Moderate volume30-40%
Lower volume15-25%

The missing piece is how many calories you’re eating per day.

That’s going to depend on your activity level (again, its highly likely you’re actually closer to sedentary than you think, even if you workout 5-6 days/week) and your lean body mass, as well as height and weight.

I’ll shamelessly plug my nutrition templates for fat loss, muscle gain, or maintenance right here, because they will tell you exactly what and how much to eat based on those things. So buy one if you are unsure of how to figure that out on your own.

Let’s put this all together so far:

 Lower Body EmphasisUpper Body EmphasisRest or Recovery
Carbs45-55% of calories30-40% of calories15-25% of calories
Protein30% of calories30% of calories35% of calories
Fat15-20% of calories20-30% of calories40-50% of calories

So far, we’ve got carbs, protein, and fat fluctuating based on how intensely we’re training, based on body-part emphasis and volume. Got it?

This is already a little beyond what most people are willing to put into nutrition and tracking, and I totally get that. This is a system that I consider ‘all things ideal.’

Now, let’s make it even more complicated by adding in the variable of calories fluctuating, too.

Because, if you’re eating the exact same amount of calories on rest days that you’re eating on lower body days, and your calories on lower body days are at or above your TDEE (refer to my nutrition templates if you’re in need of help here), then its likely you’re overeating on those rest days.

So, what we need to do now, is adjust calories based on intensity/volume, which will automatically adjust your macros on those days, too.

 Lower Body DominantUpper Body DominantRest/Recovery
Total CaloriesTDEE or TDEE + 5%TDEE - 5%TDEE - 15%

As you can see, your carb levels will not always be based on the same amount of calories, therefore when I say you might take in 45% of calories from carbs on a higher carb day and 30% of calories from carbs on a moderate carb day, you’re basing those carb levels on two different calorie levels, got it?

Yes, this adds complexity, but also, yes, it yields much better body comp results than just picking a static level of any of your macros and/or calories and sticking with it long term.

Even though two days a week you’re technically not in a calorie deficit, the other five days you are. And, this method has better compliance, in my experience, because people tend to almost never feel deprived.

Higher carb days are where you stick more of your delicious carb-y foods, and lower carb days are where you stick more of your delicious fattier foods. There’s something for everyone.

To demonstrate how this applies, here’s what my nutrient cycling levels would come out to with this method:

 Lower Body DominantUpper Body DominantRest/Recovery
Carbs287 grams (1150 calories)191 grams (765 calories) 98 grams (391 calories)
Protein172 grams (690 calories)164 grams (655 calories)171 grams (684 calories)
Fat51 grams (460 calories)73 grams (655 calories)97 grams (879 calories)
Total Calories230021851955

Who Should Use Nutrient Cycling?

This is not a method that’s appropriate for everyone. Remember what I said about not every diet working the same for all people? That includes this approach, too.

However, I find that rather than there being some complex metabolic reason why this doesn’t work for someone, in every of the few cases where this approach did not yield as good of results as I anticipated, it always boiled down to poor compliance from the person (not tracking, not paying attention to daily requirements, misreporting intake, etc).

But, under certain conditions, I find this to work the best when:

  • you are open to tracking calories and macros
  • you have trouble breaking through fat loss plateaus
  • you like being able to eat foods you love

That’s really kind of it.

Don’t try this if you’re either not willing to track, or if you don’t work with a coach or dietitian that can give you the appropriate numbers you should be tracking to. It does you no good to attempt this if the numbers you’re using for calorie and macro intake are all wrong to begin with.

This is also not necessary for someone who is simply trying to lose excess body fat and hasn’t even exhausted or really applied the concept of just creating a calorie deficit. If you’re overweight or obese right now, all you need to do to lose body fat is eat fewer calories than your body burns.

Timing your nutrients and fluctuating them over the course of time will not be critical in your situation. Can you still do it? Yeah, definitely. Just make sure you know your calorie levels by intensity level for each day. That will make or break your success.

Further Explanation

Above, I mentioned that I see two main problems with repeatedly and consistently following a high carb, low fat diet: hormone crashes and digestive problems.

Here’s my explanation of why I say this, and again, observationally and in my experience, the problems that are inherent.

Applied long term (and I would define this as six months or longer), very low fat intake steals from the critical fats needed to do everything from build and repair cell membranes, the myelin covering your nerves, and create hormones.

Over time, as you eat less and less fat, and your body fat stores of it drop, too, the available pool of fat for your body to make all of the things it needs to that are made from fat diminishes.

What tends to happen, depending on the person and other variables which I won’t get into in this post, is that the body sacrifices at least some amount of hormone production in order to keep things in homeostasis.

Because our hormones ultimately require cholesterol, if we’re cutting fat back too much for too long, we run low on this critical fat. We can make cholesterol in our body, but again, if the total pool of available fat is also low, specifically from saturated fat, there’s not really much we can make it from ourselves.

Signs that you may be running a fat deficit for too long include:

  • dry or flaky skin
  • dry or brittle hair
  • dry or brittle nails
  • increased appearance of skin wrinkles
  • trouble sleeping
  • abnormal hormone levels on routine lab work
  • hair loss
  • peeling skin (eg: on your heels)
  • digestive symptoms (this leads me to the next point)

Digestive problems or symptoms are more common in women who chronically restrict fat intake than men, but I do see them in men, too. I talk briefly about this in this article I wrote for Pump, Dump, and Hump.

Basically, in a nut shell, chronically low fat intake impairs bile production in the liver and causes weak or insufficient bile in some individuals. This leads to an abundance of acid in the duodenum (upper small intestine) without enough bile to neutralize it, which creates the wrong pH for some of your digestive enzymes and neurotransmitters/GI hormones.

The result can be anything from diarrhea, to bloating and cramping, to total malabsorption of some nutrients, or displaced or overgrown bacteria, as well as impaired motility (the ability of your GI tract to move food and other substances through it at an appropriate pace, resulting in constipation and/or diarrhea).

These things don’t tend to happen with shorter fat restrictions, like a few weeks, but I do see them often when fat calorie restriction reaches into the category of 90+ days, and definitely when its over six months.

What can you do to prevent those things from happening when dieting or losing body fat? Hopefully you’ve been paying attention to this post, because change is the key word.

If you are interested in having someone customize a plan for you and help you track and stay accountable, you can check out how to work with me to get details on that.


Commenting area

  1. I enjoy you because of your own work on this web page. Ellie take interest in conducting internet research and it’s really easy to understand why. All of us know all about the lively mode you provide both useful and interesting ideas via the blog and welcome response from the others on that issue so our own princess is in fact learning so much. Enjoy the rest of the new year. You are always performing a dazzling job.

Leave a Reply

Ready to feel better than ever? Give me a call at (816) 868-5964 or email at sarahashmanrd@gmail.com.