For today’s edition of Dear Mark, I’m answering four questions from readers. First, what does an “increased risk of mortality” actually mean if everyone’s going to die in the end? Second, what makes fish heads so delicious and nutritious? Third, what is the relationship between metformin and exercise? And finally, how do you prevent frozen vegetables from getting all mushy when you cook them?
In regards to the “garbage” meat study, how does relative versus absolute risk work? Does 3% increased risk of dying mean that if my chance of dying this year based on mortality tables is say, 10%, if I eat red meat my chance of dying is 10.3%?
Yep, you got it. It means that for the duration of the study, the subjects eating more meat had a 3% higher risk of dying. Some people lived, some died.
It’s not open-ended, though (because as everyone knows, everyone dies someday). The risk is confined to the duration of the study.
Since you mentioned eating whole organisms, I was wondering if there are any specific nutritional benefits to fish heads? I can get really cheap great fresh fish heads from my fishmonger which are fantastic steamed, and I’m curious as to their nutritional value. I can’t get much data on the heads particularly—surely the eyes and fish brain must have some unique stats and benefits? And while I’m at it… could I overdose on them? How much would be too much too consume each week in your opinion?
Grizzlies know the deal. During salmon season, they camp out on the river and snag salmon on their way to spawn. They’ll often eat the brain, eyes, roe, and belly, then toss the rest. They’ll go through dozens of them in a day, focusing only on the head and belly. Why? What’s good about the head?
Let me tell you about the beauty of the fish head.
The brain: A cow brain is incredibly rich in omega-3s, especially DHA. A salmon brain is INSANELY rich in omega-3s. Not only that, they are in phospholipid form, a structure that’s far more bioavailable than other types of fatty acids. The roe of a salmon is another excellent source of phospholipid-bound omega-3s.
The eyes: Eyes in general (like yours) are also loaded with DHA. A fish eye will have even more.
But a fish head is also delicious, not just nutritious (although the two often pair up, especially when you’re talking about whole Primal foods).
You’ve got the collar, that meaty ring of flesh and skin. Any Japanese spot worth its salt will have grilled yellowtail (hamachi kama) or salmon collar on their menu. Get it—it’s a great deal and a marriage of meat, skin, and collagen.
You’ve got the cheeks, unctuous bits of tender fish meat.
You’ve got the skin, which is incredibly fatty and collagenous.
You’ve got the brain, whose nutritious merits I’ve extolled. The brain is mild.
The eyes are pretty good, too. A bit chewy with a large deposit of collagen.
And if you’re willing to get messy, you can just dissect the head and look for the meat, fat, and skin. A good-sized wild salmon head roasted in the oven with just some salt and pepper is a solid meal that leaves you incredibly satiated because it’s so nutrient-dense.
Peter Attia has noted that in healthy people (non T2D, no metabolic issues) metformin blunts the benefits of exercise, especially the Primal type of low-intensity training. It therefore may decrease mitochondrial function. In other words, the more healthy you are, the less helpful metformin may be and can possibly make you less healthy, though that is not completely confirmed. Basically, if you’re healthy and Primal and do some intermittent fasting here and there, you may at best not benefit by taking metformin. See his podcast with Iñigo San Millán for more details.
There’s definitely something to this.
According to an interesting study in older adults without chronic disease, metformin actually inhibits mitochondrial adaptations to aerobic training . Exercising increases insulin sensitivity, unless you take metformin. Exercises improves mitochondrial respiration in the muscles, unless you take metformin.
It also appears to blunt the anabolic response to strength training in older men. In this study , those taking metformin and training saw less muscle gain than those training and taking a placebo. If true, this is a big blow against metformin supplementation for this population. The older you are, the more muscle you need to stay healthy and avoid morbidity. Every gram of muscle is crucial.
And it’s not just in “healthy” people. For instance, type 2 diabetics who take metformin and exercise regularly have worse glucose control than those who do neither . The authors of the study suggest that it may be “too much of a good thing”—that trying to stack metformin and exercise leads to a counter-signal, reversing the benefits.
Metformin might make exercise feel harder . Of course, it also increases fat-burning during exercise, and if you’re not used to burning fat during exercise, a sudden shift in that direction might make your workout feel harder.
There’s a confusing relationship between exercise and metformin for sure.
I’m not sure what to think about metformin, to be honest. Another interesting study  came out in the middle of last year comparing metformin alone to an intensive lifestyle modification program for weight loss. What happened?
Around 29% of the subjects who took metformin lost at least 5% of their weight in the first year. Almost 65% of the subjects who underwent the lifestyle program lost at least 5% of their weight.
Then, they followed up to see who’d kept the weight off from year 6 to year 15.
The metformin group won this one; 6.2% of that group maintained the weight loss while just 3.7% of the lifestyle group did.
So metformin can definitely help your average person who can’t (or won’t) maintain the lifestyle changes necessary to make a real difference. But if you can maintain the lifestyle that brings so much initial success—the diet, the training, the sleep, and everything else—it’s far superior than any pill you can take.