The health benefits of certain foods eaten hot v.s. cold

Factual Questions
1

I’m putting this into F.Q. because I’m hoping for factual dietary and nutritional information.

I love making overnight oats. A dash of cinnamon ( regarded as fairly healthy ) and a spoonful of unsugared peanut butter, and it sits overnight.

I’ve come across this article on oatmeal and health benefits. It indicates that certain benefits occur ONLY when the oats are boiled.

Now, I’m not giving up a favorite breakfast. But there does seem to be some good science regarding boiling the oats.

Similarly, the issue with cooked pasta arises. It appears that it’s healthier by a good measure to cook and chill overnight pastas instead of eating them when freshly boiled.

There are multiple articles to be found that *seem to be * reputable science that address both of these issues.

Utter b.s. or something to consider when preparing foods?

Are there other instances of temperature having such a direct effect on how the body processes a food?

2

FQ response is that it is not total bullshit. Resistant starches form in some foods with cooking and cooling even reheating, and they function similar to fiber. Some foods have more or less availability of their vitamins and minerals if cooked.

The opinion answer though is that if one’s overall pattern is diverse and healthy I have a hard time believing the differences matter meaningfully.

3

Is your question about differences due to the temperature immediately as/when eaten? Or about differences whether or not the food was cooked at some point in the upstream process?

So which are you asking? Or both?

4

Clinically significant effects of starch retrogradation (as seen when cooked pasta is refrigerated for a time before being reheated and eaten) may have been exaggerated. For instance, this review found that touted effects of appetite reduction and weight loss were not substantiated.

Anecdotally, I conserve uneaten portions of pasta in the fridge, later reheating and consuming them, and haven’t noticed any effect on satiety or communications from my gut microbiota.

Taste may be an underexplored benefit of chilling cooked pasta. Calvin Trillin once reported feeling nostalgic for packaged macaroni and cheese, being unimpressed after preparing it fresh, but noting that it was better when refrigerated and later reheated.

5

Not completely the same thing, but foods taste less salty when warmer. Or to put it another way: something that tastes perfectly seasoned will seem overly salty if you eat it cold the next day. So if you’re trying to limit sodium intake, you could potentially decrease the temperature served at.

Otherwise, lots of proteins can be denatured at certain temperatures or acidity, which may make certain nutrients more or less bioavailable to the consumer.

6

Learning to master fire was a major role in our evolution. When we learned to cook food the fire helped break the food down for us (requiring less work for our digestive systems), liberated calories that would normally pass through our digestive systems unabsorbed, and killed pathogens. This whole process allowed our teeth and jaw muscles to shrink, and gave us more calories, which helped our brains expand.

Aside from that, some vegetables lose their vitamins when cooked.

Vitamin C is destroyed by heat, but beta carotine in carrots becomes more bioavailable after cooking.

7

Resistant starch forms in cooked rice after it’s cooled for several hours. I have an older Chinese friend who was brought up believing that rice had to be served at every meal and had a really hard time when her doctor told her that she needed to cut down on rice because she was diabetic. Apparently the resistant starch in cooled and reheated rice made enough of a difference.

8

My blood glucose tests a bit lower, though I haven’t investigated this rigorously and there are obviously a lot of other variables.

9

Well it is worth noting that @Jackmannii’s cite does not say that there are no clinically significant impacts. So for example from the review:

A recent meta-analysis concerning this topic included 16 clinical trials. It showed the significant effect of RS intake on the reduction in fasting plasma glucose and the homeostatic model assessment for insulin resistance index (HOMA-IR) compared to digestible starch intake. This effect was significant in people who were overweight or at high risk of developing diabetes. Furthermore, researchers showed a more significant effect when the intervention duration was longer than 8 weeks and the RS consumption dose was above 28 g per day. However, the meta-analysis conducted did not show a significant effect of RS intake on insulin-related parameters such as fasting insulin, the insulin sensitivity index (SI), acute insulin response (AIR), the disposition index (DI), glucose effectiveness (SG) and homeostatic model assessment (HOMA- β) (Xiong et al., 2020).

Some real impacts. But let’s face it - at best it is going to be equivalent to having modestly more high fiber food intake and a bit less fast digesting carbs, a good thing, but not something that in and of itself is going to suddenly be all is right is my world. And measuring real world impacts in convincing ways would take bigger studies than have been, or are likely to be, done.

I’ll stick with real but only one possible contribution to an overall diverse and healthy nutrition pattern.

And btw @Cartooniverse? I’m not seeing where your article claims oats need be cooked to be healthy? In fact it states:

If you’re time-pressed in the morning, try a healthy version of overnight oats, which can be prepared the night before.

Theoretically cooking reduces phytic acid which might marginally increase the availability of some nutrients. But that is a stretch. The high point of oats is its high soluble fiber content and that is there in overnight oats as much as when it is dissolved in the hot water of a bowl of hot cooked oats.

10

A reminder that the analysis concluded:

Right.

11

Exactly agreed. Lowering fasting plasma glucose in at risk populations is suggestive of benefit to the end points of diabetes, obesity, so on through morbidity and mortality … but not proof of those impacts. I’d put it as probably contributes to lowering risk. Maybe you’d lower it to possibly?

My point is context of impact. Probably eating the overnight oats, high in real fiber, over fresh cooked cream of rice (high in neither fiber nor resistant starch) matters much more. And both swamped by someone (not our OP) adding a bunch of maple syrup or honey or sugar to either! Both better than pancakes and syrup with bacon. Head to head long term RCT lack acknowledged. :slightly_smiling_face:

12

A bowl of unsweetened oatmeal is already a horribly inappropriate thing for a (pre-) diabetic to eat, regardless of preparation or temperature.

Sounds to nonexpert me like the difference between the resistant starch version that’s sat a day or more after prep versus the non-resistant version that was just prepared (whether hot or cold) is that a diabetic can safely eat 1 bite of ordinary oatmeal and maaybe 2 bites of resistant-starch oatmeal. All the rest of the bowl is a huge glycemic stressor best avoided.

I’m still wondering what the OP is thinking & trying to ask. Is it about cooking vs not? Is it about served hot vs cold? is it about served promptly when ready vs after a multi-hour or multi-day delay?

13

Anecdata: Oatmeal doesn’t raise my BG and has other benefits. I have it maybe twice a week.

14

The resistant starches conversation is strictly on the pasta side.

As DSeid pointed out, the OP’s link about oatmeal didn’t say it had to be boiled to be healthy, only that the soluble fiber in oatmeal, beta-glucans, “dissolves in hot water.” Another article said that it’s only about one third as soluble at 20 degrees Celsius than it is at 100 degrees. Still, you’re getting a decent amount of it in your overnight oats.

15

This is an incorrect statement.

It is a whole grain high soluble fiber grain. High in protein for a grain. Good source of several antioxidants. Completely fine as part of a diverse diet.

In fact those with diets higher in oats have decreased risk of developing T2D.

Seems to help with control in diabetics.

https://pubmed.ncbi.nlm.nih.gov/30157531/#:~:text=A%20randomized%2C%20open-label%20crossover%20dietary%20intervention%20study,the%20intervention%20might%20last%20for%20several%20weeks

The Metabolic Effects of Oats Intake in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis - PubMed*

As much as the cooked bowl has. And FWIW there is some suggestion that overnight oats might have a lower glycemic index than cooked oatmeal does but that is not clear to me.

Oh. The resistant starch conversation is not just pasta. Many other foods as well. Potato most famously.

16

My O.P. was addressing whether there were genuine health benefits to eating hot cooked oatmeal opposed to overnight cold water oats.

Also, the linked article addressing the impact of eating freshly boiled pasta to pasta that had been fully boiled, cooled, refrigerated overnight and re-heated.

I was asking for more detailed info, not proposing that I had the answers. Was, as we used to say here, looking to Fight Ignorance.

17

and Lycopene is better absorbed from cooked tomatoes versus raw

18

Indeed you consume the same amount of soluble fiber but more of it undissolved. I imagine it would be similar to simply consuming more insoluble fiber.

I was referring to the conversation in this thread. Although, resistant starch might explain why overnight oats have a lower glycemic index.

19

Well, the raw oatmeal i usually have for breakfast spikes my blood glucose. At least, the bowl of raw oatmeal, blueberries, coconut flakes, nuts, and whole milk that usually have for breakfast spiked my bg when i was wearing a continuous glucose monitor.

Weirdly, the meal that most reliably spiked my blood glucose the highest was lentils and rice. That was worse than, say, beef with oyster sauce and rice. Maybe it was the lack of fat in the lentil meal.

But lentils have lots of other health benefits. While it’s interesting to pick apart whether this nutrient is more or less available with that preparation, i think nutrition needs to be looked at in aggregate.

Is this thread supposed to be just about the factual question of the effects on nutrition of cooking oatmeal and pasta? On the (different question) effects of letting the cooked starchy foods sit in the fridge for hours before eating them? Something else?

20

No, it really is most similar to consuming the same amount of soluble fiber. :slightly_smiling_face:

The main reason for the hypothesizing a lower glycemic index for overnight oats is that cooking “gelatinizes” the starch, making it easier to absorb more quickly.

Interesting thought that cooked and then cooled oats might also have that retrograde resistant starch in addition to the soluble fiber!

Complete agreement!!

Again I don’t believe these items are of no significance. But they are trees not forest and forest matters much more.

Part of me is curious to know what breakfast meals at same time of day with similar levels of satiety did much better for you, but for the broad discussion it really is immaterial. For general purposes unsweetened oatmeal, as you eat it, with milk, nuts, coconut, and fruit, as the OP eats it with peanut butter and cinnamon, is a great nutritious choice, for most people, including most with prediabetes and diabetes. As part of the complete forest of a sustainable diverse healthful diet, (generally speaking whole food and plant forward focused). I think we can tie this back to a previous thread about the trend in some circles to obsess over flattening their glucose curve as THE metric that matters: not something that is going to necessarily guide to the best long term health outcomes.

Maybe I missed some subtlety but it seemed straightforward to me?

Is there really much of an impact nutritionally based on eating various foods cooked vs raw, cooked and then cooled, that and then reheated? Or is it just BS?

And my response remains that there are real measurable impacts, such as resistant starch formation, destruction of some vitamins, better availability of others, but that in the wash of a broad diverse nutritional pattern they are highly likely relatively trivial impacts.

If someone is looking for the one simple hack to good health eating cold pasta probably won’t be it. :slightly_smiling_face: