Two listener questions about sugar and protein.
Are smaller amounts of sugar spread out over the day better than eating it all at once?
Nutrition Diva is hosted by Monica Reinagel. A transcript is available at Simplecast.
How to build muscles with less protein: https://nutrition-diva.simplecast.com/episodes/448-how-to-build-more-muscle-with-less-protein
How to build muscle on a plant-based diet: https://nutritionovereasy.com/2016/11/how-to-build-muscle-on-a-plant-based-diet/
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Hello and welcome to the Nutrition Diva podcast. I’m your host, Monica Reinagel, and today I have two listener questions. The first one (from Tal) has to do with sugar; the second (from Ella) is about protein. But both Tal and Ella are asking the same thing. Is there any benefit to spreading your intake over several meals as opposed to eating the same amount in a single sitting?
Let’s start with Tal’s question about sugar:
“Should I spread out my sugar consumption? For example, after eating dessert, is it better to wait a couple of hours before having coffee with sugar? That way I’d get less of a sugar spike.”
Specifically, Tal seemed to be concerned that higher blood sugar spikes might lead to insulin resistance.
Just to quickly review, Insulin is a hormone released by the pancreas that helps clear glucose out of the bloodstream and into cells, where it can be used for energy or stored for future use. Insulin resistance means that our cells have become less responsive to the effects of insulin. As a result, our blood sugar levels remain inappropriately high. Insulin resistance can be a precursor to full-blown Type 2 diabetes.
A lot of us worry that eating too much sugar or eating it too often increases our risk of insulin resistance or Type 2 diabetes. But now we understand it's more the other way around: Insulin resistance (or poorly controlled diabetes) results in chronically high blood sugar.
It turns out that eating a lot of sugar, or even just eating foods that are rapidly converted into blood sugar (such as white bread), are not the primary factors in the development of insulin resistance. The primary factors are excess body weight (especially around the waist) and a sedentary lifestyle. Age and genetics also play a role. We may be genetically disposed to insulin resistance. But either way, our cells may become more resistant to insulin with age.
Now, that doesn't mean that eating a lot of sugar doesn't have any consequences. If your body weight starts to drift up (whether from overeating sweets or any other food), that does increase your risk of insulin resistance.
In other words, for those who do not have diabetes or insulin resistance, the short-term impact of sweets on your blood sugar is probably not as big a concern as the long-term impact of sweets on your body weight–or on your nutrition. (Because if you’re eating a lot of sweets, they may be crowding other more nutritious foods out of your diet.) And by the same token, for someone who does not have diabetes (or pre-diabetes), the timing or spacing of your sugar intake is probably not as important as the total amount of sugar you’re taking in.
If you’re interested in improving your insulin sensitivity, I have three strategies to suggest. First, regular exercise improves insulin sensitivity, in those both with and without impaired insulin response. Regular intake of artificial sweeteners (in particular sucralose or Splenda) has been shown to have negative effects on insulin sensitivity–just one more reason you might want to limit your intake of those. And finally, an under-appreciated way to improve your insulin sensitivity is to space your meals out more. For example, eating two or three larger meals with several hours between them, instead of grazing throughout the day, can improve your insulin sensitivity.
Now, let’s turn to the question about protein. Ella wrote to ask for clarification about something I’ve talked about before: the potential benefits of distributing your daily protein foods more evenly throughout the day, rather than eating most of your protein at dinner–which is the typical pattern.
Ella’s question offered the additional attraction of getting to wade into a marital dispute (you know how much I love that).
“My husband is on a huge protein kick,” she wrote. “When I saw him eating a protein drink, eggs, and yogurt all at the same meal, I mentioned (lovingly of course) what you had said about the added benefit of spreading your protein intake out across meals vs eating it all at once.
“He was very eager to tell me that’s not actually true—that the body can store amino acids in the small intestine and the body can utilize them later. I’m curious to hear your thoughts.”
Now this doesn’t happen very often in the nutritional marital disputes I’m called into to mediate but in this case, both Ella and her husband are actually correct.
The body does store amino acids for future use. And the oft-repeated dictum that the body can only absorb or utilize 30 grams of protein in one sitting is a misunderstanding, or, at least, a gross oversimplification.
Increasing the amount of protein in a meal has been shown to increase muscle protein synthesis–but only up to a certain point. After that threshold, adding more protein to the meal does not lead to more muscle protein synthesis.
In younger folks, that threshold is around 25 grams–and that’s assuming a high-quality protein source like whey protein or chicken or beef. If you were getting your protein from plant sources, you might need more.
However, for people over 40, it may take 30 or 35 grams of high-quality protein to hit that peak muscle protein synthesis threshold. This phenomenon is referred to as anabolic resistance. Similar to insulin resistance–where the cells become less responsive to the effect of insulin–anabolic resistance is when the cells become less responsive to the effects of protein.
In any case, there is a threshold beyond which eating more protein at a single meal doesn’t further enhance muscle protein synthesis. But that’s not to say it can’t be utilized.
Dietary protein serves more than one function in the body. Yes, it is used to build and repair muscle. But protein also supplies the building blocks for enzyme and hormone production. Proteins are involved in cell signaling and repair and brain function. And, of course, protein can also be used as a source of fuel or energy.
So, when people say that the body’s ability to utilize protein tops out at 30 grams per meal, what they really mean is that the body’s ability to utilize protein to synthesize muscle tops out at about 30 grams per meal. The rest will be put to other purposes.
Now, it sounds like Ella’s husband–with the protein shake and eggs and yogurt all at the same meal–may have been over that threshold. And Ella’s right: In terms of building muscle, you’d get more benefit from eating two meals, each containing 30 grams of protein, than from a single meal containing 60 grams.
But this may only be relevant for people who can’t or don’t want to eat more than 60g of protein per day. If they’re trying to maximize their lean muscle, they’d be better off splitting that up over two meals than eating it at a single meal.
For people who are happy to eat 100 or 120 grams (or more) of protein per day, exceeding that threshold of 30 or 35g of protein at any given meal probably won’t be as much of an issue– because they are still likely to hit that optimal muscle building dose two or more times a day.
And just in case you’re wondering (as I was), my protein researcher friends estimate that you’d need to have at least 2 hours between meals to reset that muscle protein synthesis capacity.
For those interested in how to build more muscle with less protein, I have a link in the show notes to a previous episode on that topic. And for those interested in more information on building muscle on a plant-based diet, I’ll include a link to an article on that.
If you take in more protein than your body needs for its various protein-specific functions and more than it can put to immediate use building muscle, the rest will be used as fuel–just like carbohydrates and fats. If you consume more calories than your body needs to fuel its activities, the excess will be stored as fat. And that’s true whether the excess calories come from carbohydrates, fats, or proteins.
However, protein does offer a couple of potential advantages as an energy (or, calorie) source–particularly for those who are trying to lose weight or avoid gaining it. Protein requires more energy to digest, so a higher protein diet will give your metabolism a modest boost. I don’t want to overstate the impact of that. More relevant, in terms of weight management, is the fact that calories from protein keep you full for longer than the same amount of calories from fats or carbohydrates. That can make it easier to eat a bit less.
Of course, sometimes we eat for reasons other than hunger… such as stress or boredom. A lot of the people I work with on weight management tell me that emotional eating is an even bigger challenge than managing their appetite. And if that sounds like you, you may be interested in a program that I’m offering on Overcoming Stress and Emotional Eating. We’re kicking it off next week and you can find details on that at weighless.life/stress
If you have a nutrition question (or, even better, a nutritional marital dispute) send it to me at nutrition@quickanddirtytips.com or leave it on the Nutrition Diva listener line at 443-961-6206. and your question could be featured in a future episode!
Nutrition Diva is a Quick and Dirty Tips podcast. It's audio-engineered by Nathan Semmes with script editing by Adam Cecil. Thanks also to Morgan Christianson, Holly Hutchings, Davina Tomlin, and Kamryn Lacy.