Macronutrient Ratios in Plant-Based Diets
When I was conducting my research in grad school, I had to create menus for a vegan-based, low-carbohydrate diet and a vegetarian-based low-carbohydrate diet.
Sounds simple, right?
Well, as some of you may presume, not necessarily.
This is because many plant-based proteins are also high in carbohydrates. For example, you probably know that beans and lentils are a good plant-based protein source. This is absolutely true. But, beans and lentils also contain a decent amount of carbohydrates. So when I was designing these meal plans, I would add foods like beans and nut butters to the menus… only to find that while their protein intake increased, so did their carbohydrate intake.
Dietitians and nutritionists think about beans and lentils not only as a protein source, but as a carbohydrate source too.
So if you're wondering whether eating plant-based protein sources are throwing off your macronutrient ratios, I get it. Because when you eat some of these foods, like beans and lentils, you’re definitely adding protein to your diet, but you’re also adding a fair amount of carbohydrate at the same time, although it's not in direct proportion to the amount of protein you’re consuming.
How Do I Better Align My Macronutrient Ratios?
Should you be cutting back on your protein intake to better align your macronutrient ratios?
Let’s start from the beginning so we don’t confuse ourselves. Certain nutrients are called “macronutrients” because we need to consume them in large quantities daily. Hence, the term “macro” – meaning “large.”
The nutrients that we need to consume in large (or macro) quantities each day are carbohydrates, fats, and proteins. And, in case you’re wondering, since the opposite of macro would be “micro,” are there “micronutrients”? There sure are. These would be the vitamins and minerals. We need to consume smaller amounts of vitamins and minerals each day when compared to carbohydrates, fats, and protein, hence the term “micronutrients.”
There are some nutrition experts that believe that for optimal health and wellness, we should get the right ratio of macronutrient levels each day. For example, when we think about our daily intakes of just the macronutrients, some believe that we should consume 30% of our calories from protein, 30% from fat, and 40% from carbohydrates. Now, I’m not saying that everyone should be following these specific ratios — I am just using this as an example.
By using these macronutrient ratios to design menus and meal plans, the thinking is that this will help ensure enough of these nutrients are consumed each day, but possibly also help control food cravings, manage blood sugar levels, etc. Again, this is just a theory that some adhere to.
Should I Decrease My Protein Intake?
Now, if you’re consuming more beans and lentils for their protein content, you’re also adding to your carbohydrate intake. This is because beans and lentils are also decent sources of carbs but not in the same proportion as their protein content. This is potentially throwing off these macronutrient ratios. To adjust for this, I wouldn’t recommend decreasing your protein intake. This is because by cutting out meat and dairy from your diet, you’ve already reduced a number of protein-rich food sources in your diet. And, it is relatively common for folks to consume too little protein each day when switching to vegetarian or vegan lifestyle.
The 1 gram or protein per pound of body weight recommendation is pretty standard assuming you’re active. Let’s say you weigh you 125 lbs. This would mean you need to consume 125 grams of protein each day provided you’re active. You can get away with less if you’re not participating in regular physical activity or strength training.
According to the United States Department of Agriculture (USDA), women can consume as little as 46 grams of protein per day (men, 56 grams per day). Ssome health professionals have argued that this is far too low, but I’ll have to save that for a different Q&A episode. The bottom line here is that, yes, protein is important but you may not need as much you as you think.
How Do I Select Plant Foods that are also Low in Carbs?
So, what to do with all of this seemingly conflicting information?
The good news is that we know from lots and lots of studies that following a mostly plant-based diet can prevent a number of diseases. But it can be tricky when it comes to finding protein-based plant foods that are also low in carbohydrates.
Well, think about it this way: imagine an ordinary green house plant. What do you do to keep it alive? Basically, two things, right? Give it some water every now and then and make sure it’s exposed sunlight. You don’t need to feed the plant fats, carbs and protein. Why not?
It's because the plant makes its own fuel from the sun (remember photosynthesis from 3rd-grade science class?). That fuel is sugar or carbohydrates (as opposed to fats or proteins). Many plants operate the same way — not just house plants, but the plant-based foods we eat, too. Just by the very fact that a food is plant-based means it’s going to contain some carbohydrate and little fat and little protein. This was the same issue I ran into when trying to design low-carb meal plans for my study.
Therefore, if you want to maintain or increase your intakes of protein while minimizing your carbohydrate intake all while following a plant-based diet, the only thing we can really do is try select plant-based foods that are lower in carbohydrate.
Tofu is one such example. Tofu is made from soy beans, but the soy has been processed to make tofu. So, if you want to substitute tofu for, say, soy beans, you would end up consuming more carbohydrate. This is because the soy bean in its natural state contains quite a bit of carbohydrate. Soy milk would also contain more carbohydrate — but, this is because sugar (a type of carbohydrate) is often added to these products to make them taste better. Nuts and seeds are decent options, but will still contain some carbohydrate. Other than these foods, you will find that most plant-based foods are going to be higher in carbohydrate and low in protein.
What About My Intake of Micronutrients?
I must also mention that paying attention to your intake of some micronutrients is a good idea.
The most common deficiencies we see in those following a plant-based diet are vitamin B-12, vitamin D, iron, omega-3 fatty acids, and calcium.
Why? Because for many of us, we get these nutrients from animal products.
So what I would recommend is first, to consider taking a multivitamin every day. This will likely cover your iron, vitamin D, and calcium needs.
Next, find a quality vitamin B-12 supplement. The most active form of B-12 comes from animal products. You may have heard that some sea vegetables like algae contain B-12. This is true, but it’s not a form that the body can use so you need to get B-12 another way. A sublingual form of vitamin B-12 is fine. This is the form of B-12 you place under the tongue and it gets absorbed that way. Luckily, you don’t need a prescription for these.
The next supplement I would consider would be one containing omega-3 fatty acids. Finding a quality supplement is important here. There’s no need to buy a mega-dose version but try and find one that says it’s “enteric coated” and contains both EPA and DHA. You can also find omega-3 fats in sea vegetables so if you consume seaweed or algae on a regular basis, you may not need this supplement.
I keep mentioning finding a “quality” supplement. This could be a whole other podcast, but for now, a really easy trick is to look for one or both of these symbols on the outside of the supplement bottles: USP or NSF. These symbols mean the product has been tested for quality — that way you can feel confident that you are taking something that is relatively free of impurities.