Personalized Nutrition: How to find the perfect diet for you

Personalized nutrition is a hot topic these days. It’s based around the concept of bio-individuality: That each of us thrives on a diet that depends on a lot of different factors. These factors include genetics, sleep, meal composition, meal timing, physical activity, and the microbiome.

Unfortunately, this idea really doesn’t sell well. It’s much easier to buy into simple concepts, even if those simple concepts are likely false. That’s why diets that demonize particular food groups, such as Vegan and Carnivore diets, are so popular.

The truth of the matter is, I started with a restrictive diet a little back with no plans for personalized nutrition. Back in 2010, I took to the Paleo diet. As a result, I lost about 30lbs and felt great…until I didn’t.

Though, it’s important to point out that the problem wasn’t the diet, it was me. My first year of Paleo was close to picture-perfect Paleo. Tons of veggies, a varied diet, and nary a processed food.

Then came the processed Paleo treats, and a low carbohydrate Paleo diet. This coupled with high motivation to exercise simply didn’t work for me. I became sensitive to foods I was never sensitive to, my sleep was bad, and my blood glucose started to go higher and higher.

Fast forward to now, and at this point, I feel I’m dialed in, and I am not restricting anything at all:

A1c test results
My most recent A1c test

For those that don’t know, that’s a fantastic A1c reading. It’s equivalent to having an average 3 month blood glucose of 90mg/dL, or 5.0 mmol/L. And this is with a ton of carbs, more than 300g/day(I don’t really count anymore). Note: We’ll discuss this measurement with nuance a little later.

It seems as though I’ve gotten ahead of myself. Let’s start from why I went Paleo in the first place.

Why I went Paleo

Back in 2010, I was 220lbs. I had just done a Keto diet to drop down from 236lbs, and it worked great. But, I still had more to lose and I didn’t want to go Keto for life. I like carbs and beer.

My last check-up with the doctor flagged me as pre-diabetic with a fasting glucose of 110mg/dL. He said not to worry about it because it was only my first bad reading, just try to lose some weight. So I did, and a year later after 6 weeks on Keto and lighter 16lbs, it was 121mg/dL and my hemoglobin A1c came back as 5.7%.

So a friend of mine recommended I go Paleo and some of it resonated with me. Looking back, my perception of its usefulness was misplaced.

It worked great as I replaced Hot Pockets with meat and veggies. It didn’t even feel like dieting. My blood glucose got into the normal range and I got down to 195lbs, my first time under 200lbs since college 10 years earlier.

But then I went lower carb Paleo. I still had some veggies in my diet, but I dropped my carbs super low. I started to feel…off. On top of that, I couldn’t sleep at all and I started getting GERD.

Ultimately, it wasn’t the Paleo diet that was the problem, it was my approach to nutrition. My approach was wrong, and as a result, I wasn’t applying the principles properly. A restriction diet is a starting point for personalized nutrition, not the answer.

Unfortunately, I think this is the approach most people take, and as a result, they end up eating only a handful of foods.

The Paleo diet: A starting point for personalized nutrition

There are a couple of basic tenets behind the Paleo diet. Probably the most important concept one can grasp from the diet is that we eat too much processed food and not enough whole foods.

To this day it’s still a concept central to how I eat. I do eat some processed food regularly. Though, the vast majority of what I eat is whole and unprocessed.

But the second tenet was where I screwed up. This states that some neolithic foods are immunogenic, meaning they can stimulate an immune response. It’s important to emphasize the can in that statement.

Grains, legumes, and dairy are classifications of foods that are potentially immunogenic. Certain individuals are allergic to these foods, so limiting them may help you identify foods you may be sensitive to. But that doesn’t mean they’re bad for everyone, or that you eliminate them from your diet permanently because they’re bad.

My logic wasn’t consistent, however. I ate eggs everyday, and eggs also fit the bill as a common allergen. Ironically enough, when I was a kid I induced an egg intolerance because I’d eat 9 eggs a day, every day. Fortunately it went away when I cut back to a normal amount.

But just because Karen is allergic or sensitive to soy or wheat doesn’t mean I was. Restriction diets like the Paleo diet are a starting point for a personalized diet. At least if used properly.

Ultimately, one of the most important things I found out from going Paleo was that I am sensitive to cow’s milk, but not cheese. If I eat enough, I’ll get eczema. I can eat it, just not a ton of it everyday.

Thus, the Paleo diet was a useful first step in developing my personalized nutrition plan, but I just stopped there.

Diet tribes: The enemy of personalized nutrition

For me, it’s always been clear that nutrition is a very personal thing. It’s personal in that some people simply prefer some foods to others.

It’s also personal in that different people thrive under different diets. And some of us can thrive on many different regimens, which allows preference to play a bigger role. That’s definitely me.

I like carbs, beer, bacon, and sneaking a few of my son’s treats. I also like not having a list of food restrictions when I go out to eat or to a friend’s house. Now, I don’t suspect anyone likes to restrict foods if they don’t have to. Unfortunately restriction begets more restriction from my perspective.

But what I didn’t like, and what I was starting to do, was judging what people ate. Though rarely, I’d comment if it was someone I was comfortable with.

“You shouldn’t eat that, gluten is bad for your gut!” Ironically, a gluten free diet actually depletes some beneficial bacteria that protect against allergy and leaky gut. That doesn’t mean people with Celiac disease should start eating gluten.

“Don’t eat soy, it has phytoestrogens that increase your risk for hormone-sensitive Cancers and if you’re a guy can give you gyno!” Those phytostrogens actually reduce the risk of hormone-sensitive Cancers, inhibit aromatase which is the enzyme that converts testosterone to estrogen, and some actually lower estrogenic activity.

That’s the funny thing I found out about diet tribes and diet books. When you actually look up the citations for many of their more outrageous claims, the citation is either wrong or misleading.

Misleading claims from diet tribes

Generating misleading claims seems to be very common with the more extreme diets such as Vegan or Carnivore. With Vegans it’s about meat, with Carnivore it’s about plant toxins.

If you look into these things, they’re straight out false. Meat is beneficial for maintaining muscle mass as you age. And plant toxins such as oxalates are not human toxins if people who eat more of them have better health outcomes.

But, epidemiological data is flawed, right? No, epidemiological data is useful if you use it properly, as a guide to how foods affect populations. Like restriction diets, they’re useful as a starting point, but not for drawing conclusions on precisely what you should eat. We require trial and error for a personalized nutrition plan.

The problem with a lot of the diet tribes is that people try something, it works for them, and they conclude that it’s the best thing for everyone. Then, they begin looking for studies to back up their theories, and they share that information with friends and family.

At that point, anyone doing anything different is poisoning their body.

Plant toxins and the Carnivore crowd

Plant toxins are the target of the Carnivore crowd. It’s hard to reconcile that plant toxins are a major problem for most since eating more plants generally leads to lower mortality risk.

That doesn’t mean you don’t have a problem with some components of plants or that you should only eat plants. But it’s unlikely you have a problem with all plants, or that everyone is sensitive to them.

In the case of oxalates, people who consume more, aka Vegans, aren’t more likely to get kidney stones than the rest of the population. They actually have a lower risk. Based on the data, a healthy person makes about 50% more oxalate than they eat on the higher end of normal oxalate consumption.

I’ve heard people say several times that we make an insignificant amount of oxalate in the body, always people arguing we shouldn’t consume plants because of the toxins. The problem is it’s been studied, the data is there.

A healthy person consuming 250mg of oxalate per day gets 40% from their diet, meaning they and their microbiome make the other 60%. Now, if you cut their calcium intake from 1000mg to 400mg, this increases dietary contribution to 52%.

But I don’t know what world you live in if you believe 40-50% of total exposure is an insignificant amount, or that something you make a ton of in your body is a toxin. This number likely skyrockets if you have diabetes, which increases endogenous oxalate production. We covered the ins and outs of oxalate in a blog you can check out here.

And if you look at the case studies they reference showing oxalate consumption to be a problem, it’s almost always in a diabetic…or an alcoholic…or both. At worst, oxalate is a metabolic by-product we have a limited capacity to deal with, most of which is made in our body.

Meat and the Vegan crowd

This same process plays itself out with Vegans. It’s hard to argue that the standard American diet isn’t too heavily skewed towards meat consumption, processed meat in particular.

But it’s quite a leap to go from too much meat is bad to no one should eat meat. Meat is an important part of a healthy diet, and eating more meat is associated with better maintenance of muscle mass as we age.

It may seem insignificant, but maintaining muscle mass is incredibly important for healthy aging. Frailty is a leading cause of morbidity in older folk; muscle mass matters a lot. It’s also important for maintaining healthy blood glucose control

The PREDICT STUDY: Personalized Nutrition for the 21st century

PREDICT study for personalized nutrition

Arguments about extreme diets aside, we are making progress on the personalized nutrition front. Preliminary results from the PREDICT 1 study were published last year. PREDICT stands for Personalized Responses to Dietary Composition Trials, and is a series of studies meant to untangle individual metabolic responses to food.

The PREDICT trial feeds people biscuits of varying macronutrient content and follows their post-meal metabolic responses. They primarily look at triglycerides, insulin, inflammation(CRP) and blood glucose. The results thus far are interesting.

While individuals tend to have similar responses to the same biscuit from day to day, 2 people can have a wildly different response to the same biscuit. The goal of the study is to identify factors that dictate a person’s response to food to develop an algorithm to help people determine what’s best for them.

They’ve identified some interesting factors that drive an individual’s metabolic response to food. Sleep, meal composition, meal timing, physical activity, and the microbiome are all important.

Interestingly, your response to food changes based on what you ate in prior meals, the previous day, and whether it’s the first meal or last meal. It also changes based on whether you stick to 3 meals or eat snacks in between. They found that snacking in between meals leads to an exaggerated metabolic response to the subsequent meal.

Although there were general trends, there were also outliers who responded in the opposite manner than the “average”. For example, 3 out of 4 people did better eating larger meals earlier, while 1 in 4 did better eating eating larger meals later. This underlies the importance of self-experimentation.

Most studies identify average trends in the study population, but your response may not be average. And if your response is not average, following the average may get you into trouble.

Personalized nutrition: Measuring your metabolic response to food

Each year I make changes to my lifestyle and diet. I follow up those changes by looking at data throughout the year to determine if what I’m doing is something I should continue to do. I typically look at activity tracker data, heart rate variability, oral glucose tolerance testing(OGTT), and Hg A1c as my primary measures.

OGTTs are important because A1c is not a lousy measure on it’s own for certain people. For all, you may have a good A1c, while at the same time having wild fluctuations in post meal blood glucose.

For example, if your A1c calculates to a 3-month average of 95mg/dL, but your typical meals cause it to spike to 180mg/dL, that means it’s dropping very low afterwards. Stable is good, wild fluctuations are bad holding A1c constant.

Generally speaking in a healthy person, an A1c of 4.7% isn’t where you want to be. The epidemiological data points to ideal being around 5.0%. But, again, there are many ways to get to 4.7%.

My glucose first thing in the morning is 95 mg/dL, and most meals it goes up to ~140mg/dL and back down to 90mg/dL within 90 minutes. By later in the evening, it’s around 85 mg/dL. So it’s low but stable, which is what I aim for.

Since I only eat 2 or 3 meals a day, I spend very little time in the post-meal state during the day. This is one of the reasons my A1c is where it is, coupled with my daily physical activity level.

Unfortunately, I’m unable to test either insulin or triglycerides, but my TGs are excellent at my check up. They’re always 55mg/dL or lower.

Things I changed this year

Each year I feel I get closer and closer to my ideal lifestyle. I thought I was pretty dialed in a couple of years ago when I started the circadian stuff, but it’s clear I’m still making progress.

My sleep is better, energy levels are consistent throughout the day, mood is great, and digestion is rock solid. There were some foods that would cause digestive issues such as beans and greens a couple of years ago, but no more.

The things I incorporated over the last year include:

  • Going to bed later
  • Earlier but more consistent exercise time
  • Less total exercise, more play with my 4 year old
  • Strength training at lower intensity (Thanks COVID!)
  • Less cardiovascular exercise
  • Discontinuing all supplements save for a multi-vitamin and collagen
  • Took out weekly 24-hour fasts
  • Eliminated multi-day fasting
  • Consume less meat (I generally ate it at every meal)
  • Upped fiber from 30g/day to 50g/day
  • Incorporated fermented soy most days
  • Incorporated more fermented foods in general
  • Increased polyphenol content
  • Chamomile tea after dinner(Improves sleep)
  • Decaffeinated green tea at “Tea time”
  • Measure weekly alcohol intake (For reference & potential decrease next year)

Overall, it’s been a very successful year in terms of improving my health. My HRV is higher, sleep is better, and I feel great!

Over the next couple of weeks, I’ll figure out my plans for next year.


If your goal is to live a long, happy, and healthy life, you should shy away from diet tribes and move more towards a personalized nutrition program. If some of the restriction diets appeal to you, they can function as a decent starting point, particularly if they lead to a healthier weight.

But it’s important not to drink the Kool-aid too much. Realize that people writing books or in diet tribes tend to take a very myopic view towards diet. And just because something worked for your friend doesn’t mean it works for you.

Fine tune the diet to your specific needs and wants. Always be tinkering, and have a plan to measure your progress. Ultimately, a personalized nutrition plan is the ideal plan for you.

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