How to Eat According to Your Carb Tolerance
There’s no single solution for eating the right mix of carbohydrates, fats, and proteins. Here’s how to find your personal optimal mix to get fit and have great energy.
I’ve been studying how fat and carbohydrates affect the body every since I first learned about low-carb dieting over a decade ago. There’s a lot of misinformation out there, and the popular media tends to swing wildly between advocating low-carb and low-fat diets.
What I’ve learned is that the answer isn’t so simple — the right diet is different for different people. You have to eat according to your own body’s carbohydrate tolerance.
The other day I received a text message from Steve, a former client of mine. “I’m finally there. 75 kg.” Accompanying the message was a mirror selfie. For the first time since he was in junior high, Steve had a flat stomach, with a hint of abdominal muscle showing.
On my advice, Steve had been working out several days a week, but he owed most of his success to his diet. It wasn’t the Atkins Diet, the Paleo diet, or the South Beach Diet. It was Steve’s diet—one that I designed just for him, to provide his optimal mix of fat, carbohydrates, and protein.
Other clients of mine have lost weight, have gained energy, and have been able to train harder through their own personal mix of fat, carbohydrates, and protein. In each case, I help the client do their own testing to find their personal optimal mix of macronutrients.
In this article, I’ll explain how you can do that, too. But first, a quick primer on how fat and carbohydrates are processed in your body, why there’s not a one-diet-fits-all solution, and why testing to find your own optimal diet does work.
A Brief Summary of The Carb Wars
From the mid-20th century up until the 1990’s, the standard medical dogma was that low-fat, high-carb diets were the way to go. It helped that the arguments in favor of this diet were very straightforward: fat has nine calories per gram, while carbohydrates only have four, so fat should be much easier to overeat. Additionally, dietary fat can be transported straight to your fatty tissue for storage, while dietary carbohydrates have to be processed by the liver. So eating fat should, it seems, lead to fat gain more easily than eating carbohydrates.
Beginning in the 90’s, opinion began to swing in the other direction, towards low-carb dieting. Low-carb advocates like Dr. Atkins pointed out that dietary fat is necessary for satiety and steroid hormone (testosterone, estrogen, cortisol, etc) production, and is also needed for structural uses—our brains are largely made of fat, for instance.
The low-carb movement blamed high carbohydrate intakes for the modern obesity epidemic, arguing that eating carbohydrates causes your body to produce insulin, and insulin causes your body to store energy in fatty tissue. Therefore, carbohydrates are more fattening than fat, on a calorie-for-calorie basis. They further blamed insulin for making carb-eaters hungrier, causing them to overeat.
This argument contains two major flaws. First, insulin is an energy storage hormone which acts on all body tissues, not just fatty tissue—it also causes your muscles and vital organs to store energy. Second, insulin actually suppresses appetite by ensuring that the brain is adequately supplied with energy.
The Surprising Science of Carb Tolerance
Unsurprisingly, the low-fat vs. low-carb question has been studied to death. Many studies find low-carb diets to be superior, but that seems to be because low-carb diets tend to be higher in protein content. When low-carb and low-fat diets with similar protein contents are pitted against each other, they tend to produce very similar results, on average.
However, “on average” is a hugely important caveat. Individuals vary tremendously in their response to low-fat and low-carb diets, so there is no one-size-fits-all answer here.
Several studies have found correlations between blood markers of carbohydrate metabolism and response to high-carb vs. low-carb diets. People with elevated fasting blood sugar and insulin levels tend to feel better and lose more weight on low-carb diets, while people with normal blood sugar and insulin levels are usually better off eating their carbs.
Of course, tests that you do with a typical home blood glucose meter can only tell you so much. They only give you a snapshot of your blood sugar and insulin levels at a single point in time, and only look at some of the factors that determine your carbohydrate tolerance. I’ve had my blood sugar tested a few times, but I don’t rely on it to gauge my carbohydrate tolerance, and I don’t usually urge my clients to get theirs tested either.
In practice, there’s a better and easier way to gauge your carbohydrate tolerance.
The Simple Self-Experiment to Determine How You Should Eat
I’ve devised a simple way of gauging your own carbohydrate tolerance that I recommend to my clients. Because your gut feeling for how you should be eating isn’t very accurate, you get better information by collecting actual data. The way you acquire that data is through a controlled self-experiment.
What you’ll do in this experiment: eat a few meals of different types with three different carb/fat balances, under controlled conditions. After each meal, you’ll measure things like your mood, hunger, and energy level to see which meals make you feel the best.
Here’s a step by step guide for running the experiment.
Step 1: Decide what time of day to eat your test meals
Although you probably eat three meals a day, you should pick just one of those meals to be the one you run your experiment on. As with any experiment, you need to control as many variables as possible, including what time of day you’re eating— so you’ll also want to standardize the time at which your test meals take place. For instance, you might run your tests at breakfast at 8 AM every day, or lunch at 1 PM, or dinner at 6 PM.
Of all these options, I recommend choosing breakfast if at all possible, because it allows you to control for another set of variables: what happened earlier in the day. Breakfast, more so than lunch or dinner, tends to take place under the same conditions almost every day.
Step 2: Determine the macronutrient amounts for each variation
In this experiment, you’ll be testing three diets: low-carb high-fat, low-fat high-carb, and moderate-carb moderate-fat.
After that, you may also want to test other, more specialized diets, like ketogenic, paleo, vegan, or a protein-sparing modified fast. But start with the first three. These can be sustained indefinitely, and don’t require you to completely avoid any particular food. Your results on these three variations will also be helpful information in considering further specialization, should you decide to do so.
You should test each diet at least three times—so your experiment will take at least three days for each diet you’re testing.
We assume that you eat three meals a day, are moderately physically active (light workouts a few days a week), are in pretty average shape, and want to eat to maintain your current weight. Here are some guidelines for what the test meals should look like — for a person who weighs 180 pounds, and for a person who weighs around 130 pounds:
- 180 pounds: 50 grams of protein, 35 grams of fat, 90 grams of carbs
- 130 pounds: 35 grams of protein, 25 grams of fat, 75 grams of carbs
- 180 pounds: 50 grams of protein, 10 grams of fat, 150 grams of carbs
- 130 pounds: 35 grams of protein, 5 grams of fat, 125 grams of carbs
- 180 pounds: 50 grams of protein, 60 grams of fat, 30 grams of carbs
- 130 pounds: 35 grams of protein, 45 grams of fat, 25 grams of carbs
Note that all of these meals are moderately high in protein, adding up to about .8 grams of protein per day per pound of bodyweight. But we’re keeping the amount of protein consistent: the scope of the experiment is just about fat and carbs.
Of course, you can and should scale these numbers up or down to account for your actual body weight. You don’t need to get too hung up on the exact size of the meals though—it’s okay if they’re a bit bigger or smaller, as long as they maintain roughly the same ratio between protein, fat and carbohydrates as the examples given.
Step 3: Plan your meals
Once you’ve figured out the nutritional contents for your meals, it’s time to plan the specific foods you’ll eat each day. Again, you’ll need at least three meals of each type.
I recommend pre-planning all of your test meals before you start the experiment.
Here are a few examples of each type of meal:
Moderate-fat, moderate-carbohydrate meals
Meal 1: Three soft tacos with beef or pork, cheese, cabbage, and beans. No rice or sour cream.
Meal 2: Club sandwich with wheat bread, chicken, bacon, tomato, and light mayo. Side salad and cup of fruit.
Meal 3: Pulled pork sandwich with two slices of wheat bread and 5 oz pork, 4 oz mac and cheese, 4 oz broccoli, and an apple.
High-fat, low-carbohydrate meals
Meal 1: 6 oz salmon fillet, 8 oz stir-fried vegetables, 4 oz of blueberries
Meal 2: 3 eggs scrambled with ground beef, tomatoes and avocado, 3 oz of strawberries, 3 oz of carrot sticks dipped in peanut or almond butter.
Meal 3: 6 oz of meatloaf with ketchup, side salad with oil or ranch, half an avocado, handful of mixed nuts, one baby orange.
Low-fat, high-carbohydrate meals
Meal 1: Chicken burrito with rice, cabbage, and beans- no cheese, sour cream or avocado. Can of sugared soda or 4 oz of fruit.
Meal 2: 3 eggs scrambled with turkey, lettuce and tomatoes. Small bowl of cereal. Glass of juice.
Meal 3: 8 oz pasta with 5 oz chicken or shrimp, tomato sauce, 6 oz mixed vegetables, and a small piece of fat-free chocolate.
Each of these meals are sized for someone who weighs around 150–160 pounds and is moderately active, and comes out to somewhere between five hundred and seven hundred calories. Scale up or down as needed. Click here to continue reading the article.
- by John Fawkes