8/21/2026

This is the eighth piece in my series about Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity.

So far, I've been focusing on Chapter 3, “Lifestyle+.” Today, I'll cover the section on exercise.

First, exercise may be the most powerful “medicine” we have.

Topol makes a very strong claim: regular physical activity may be the single most effective intervention we know for healthy aging.

Exercise benefits the cardiovascular system, brain, muscles, pancreas, liver, immune system, blood vessels, and gut microbiome. It also improves insulin sensitivity and mitochondrial function.

Second, exercise is strongly associated with longer life and better health.

Large studies consistently associate physical activity with lower mortality from all causes, cardiovascular disease, and cancer, as well as better sleep.

One analysis of 196 studies involving more than 30 million people found about a 31% reduction in all-cause mortality associated with physical activity.

But Topol also points out an important nuance: more isn't necessarily infinitely better. Some evidence suggests that the benefits may plateau around:

• Moderate exercise: 300–600 minutes per week

• Vigorous exercise: 150–300 minutes per week

The goal, therefore, isn't to exercise as much as possible, but to exercise regularly and consistently.

Third, you don't need to hit 10,000 steps every day.

The famous 10,000-step-a-day target was not originally based on scientific evidence. Studies show meaningful benefits beginning at much lower levels.

For example, among older women, reduced mortality was associated with walking as few as 2,700 steps per day, with benefits increasing and then leveling off at around 7,500 steps.

So move more, walk regularly, and increase your pace or intensity when you can.

Fourth, aerobic exercise alone isn't enough as we age.

Topol considers exercise to have two essential dimensions: aerobic conditioning and strength/resistance training.

Muscle mass and strength begin declining around age 50. Between ages 60 and 90, men lose roughly 33% of their muscle mass, while women lose about 26%.

Strength training helps preserve muscle mass and strength, as well as bone density, balance, mobility, posture, and independence.

For older adults, maintaining muscle isn't simply about looking fit. It is about maintaining the ability to live independently.

Fifth, grip strength is a useful marker of overall strength.

Topol emphasizes hand-grip strength. Across 48 studies involving more than 1.1 million people, stronger grip strength was associated with lower all-cause mortality.

Grip strength also declines by more than 2% per year after age 50, on average.

Although this association does not prove that increasing grip strength itself will make someone live longer, grip strength is still a useful measure of functional strength—and it matters for many everyday activities.

Sixth, balance becomes increasingly important.

Topol recommends the one-leg stand as a simple measure of balance.

For seniors, he suggests being able to stand on one leg for at least 30 seconds. Inability to stand for 10 seconds was associated with roughly twice the risk of all-cause mortality.

Balance can be improved through simple exercises such as standing on one leg or practicing heel-to-toe walking. Yoga and Pilates can also help with balance and flexibility.

Seventh, sitting for long periods is itself a problem.

Topol said, "There’s one thing you don’t want to do for any prolonged period: sit." Because exercise doesn't erase the consequences of prolonged sitting.

A large study found that people who mostly sat at work had 16% higher all-cause mortality and 34% higher cardiovascular mortality, even after adjustment for other factors.

The key is to break up prolonged periods of sitting.

Eighth, and perhaps most encouraging: it's never too late to start.

You don't have to have been an athletic person when you were young. Starting later in life can still make a meaningful difference.

Topol gave an example of "Richard Morgan, 93-year-old man, who took up regular exercise for the first time in his life in his 70s using a rowing machine in his backyard shed, with an average 40-miniute workout each day."

For healthy aging, think of exercise as a lifelong investment in your heart, brain, muscles, bones, metabolism, immune system, balance, and independence.

For older adults, Topol's practical formula is:

Move regularly + walk briskly + do aerobic exercise + build muscle + train balance + strengthen your grip + avoid prolonged sitting.

And there's no better ending than Topol's own words:

“If I’m going to be old, I’d rather be strong and old!”

8/20/2026

This is the seventh piece in my series about Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity.

One of the most popular ideas in the longevity world today is calorie restriction and fasting. Could simply eating less—or eating only during certain hours—help us live longer and healthier?

Topol's answer is intriguing, but far from a simple yes.

1. What is calorie restriction?

Calorie restriction generally means reducing daily calorie intake by 20–50% while maintaining a balanced proportion of macronutrients. It is different from a ketogenic diet, which drastically reduces carbohydrates and derives most of its calories from fat.

During World War I, a natural experiment in Denmark found that dietary restriction was associated with a substantial reduction in mortality.

Calorie restriction has also extended lifespan in many laboratory organisms, including yeast, fruit flies, and mice. But studies in rhesus monkeys have produced conflicting results: one found a significant increase in lifespan, while another found no difference.

And strict calorie restriction has its drawbacks. It can be difficult to sustain and may lead to loss of muscle mass and bone density, as well as impaired brain function.

At the same time, animal and human studies suggest potential benefits involving metabolic health, immune function, and possibly anti-tumor mechanisms. So it's complicated.

2. Milder alternatives: time-restricted eating and intermittent fasting

Instead of continuously eating less, people can restrict when they eat. Some common approaches include:

• 16:8: eating within an eight-hour window and fasting for 16 hours

• 5:2: eating normally five days a week while substantially restricting calories on two days

• Alternate-day fasting

• Other forms of intermittent fasting

These approaches are generally more practical than severe long-term calorie restriction.

But there is an important complication: restricting the hours in which you eat often results in eating fewer calories anyway.

That makes it difficult to determine whether the benefit comes from when people eat, how much they eat, or both.

3. Human trials have produced mixed results

The key part here is different randomized trials have produced very different results.

Some found little or no additional benefit from time-restricted eating compared with ordinary eating or simple calorie restriction.

Others found benefits, particularly when the eating window was shifted earlier in the day. Some participants experienced improvements in:

• weight loss

• body fat

• blood pressure

• glucose regulation

• sleep

• mood

Time-restricted eating also produced weight loss and improved glucose regulation in one trial involving people with type 2 diabetes.

Intermittent fasting has produced similarly mixed but sometimes promising results, including modest improvements in glucose regulation among people at risk of diabetes.

Overall, however, the evidence is not yet consistent enough to draw firm conclusions.

4. Anti-aging benefits remain unproven

This is where Topol is particularly cautious.

Despite the enormous enthusiasm surrounding fasting in the longevity community, no calorie-restriction, time-restricted-eating, or intermittent-fasting regimen has yet been definitively shown to slow human aging or extend healthspan.

There are promising findings involving metabolic and biological-age markers, but these are not the same as proving that people will actually live longer or remain healthier for longer.

Topol also warns against turning fasting into a guaranteed “wellness” or weight-loss solution.

5. The circadian rhythm may be just as important as the calories

I think the most interesting part of this discussion is the connection between meal timing and our circadian rhythm.

Our bodies operate according to biological clocks that influence:

• digestion

• nutrient absorption

• gut hormones

• metabolism

• immune function

• inflammation

Even the gut microbiome changes throughout the day. Irregular meal timing can disrupt the synchronization of these systems and impair glucose regulation.

So the important question should be “When should we eat?”

Maintaining a relatively consistent eating schedule may help keep our biological clocks synchronized.

6. A surprisingly simple practical recommendation

Until stronger evidence emerges, Topol's practical advice is much less dramatic than some of the fasting regimens promoted online:

Eat dinner early—ideally three to four hours before bedtime—and avoid calories overnight until breakfast.

In other words, rather than pursuing extreme fasting, establish a regular daily eating rhythm and avoid late-night eating.

The bigger picture

Topol is quite cautious about the popular claim that “fasting is good for longevity.”

Perhaps the most practical lesson is：

Eat reasonably and regularly, avoid eating late at night, and don't confuse a promising theory with proven longevity science.

8/19/2026

This is the sixth piece in my series about Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity.

After discussing ultra-processed foods, sweeteners, salt, carbohydrates, protein, fat, caffeine, alcohol, and red meat, Topol turns to the other side of the equation: What should we actually eat?

Good Food

1. A healthy diet is strongly associated with a longer healthspan and lower disease risk.

Large, long-term studies consistently associate healthy eating with a 15–20% lower risk of cardiovascular disease, as well as lower all-cause mortality, cancer and neurodegenerative diseases.

There also appears to be a dose-response relationship: the more consistently people eat healthy foods, the lower their risk of several major chronic diseases.

Topol's healthy eating list:

• Fruits and vegetables

• Legumes such as beans and lentils

• Whole grains

• Nuts and seeds

• Olive oil and avocados

• Fatty fish such as salmon and tuna

These are mostly whole or minimally processed foods, with plenty of fiber and healthy fats.

Olive oil, for example, has been associated with about a 20% lower risk of all-cause mortality, and consuming at least 7 grams a day was associated with a 28% lower risk of dementia in one large observational study.

Nuts and seeds are another interesting example. Despite being calorie-dense, eating a handful regularly has been associated with about a 20% lower risk of cardiovascular disease. Interestingly, nut consumption has also been associated with less obesity and weight gain rather than more.

So calories alone don't tell us whether a food is healthy. Food quality matters.

2. Fiber is one of the stars of the story.

Topol recommends roughly 30 grams of fiber a day, adjusted for age, sex, and body size.

A large body of research has associated high-fiber diets with lower risks of:

• heart disease

• type 2 diabetes

• colon cancer

• overall mortality

Fiber slows digestion, reduces blood-glucose spikes, helps regulate cholesterol, and supports a healthier gut microbiome.

One fascinating finding he mentions is that a high-fiber diet can actually reduce the number of calories absorbed by the body. In one randomized trial, participants eating a high-fiber diet absorbed more than 100 fewer calories per day, with some people absorbing more than 400 fewer.

In a memorable phrase, Topol describes it as “pooping calories instead of absorbing them.”

This is almost the opposite of the ultra-processed-food diet.

Ultra-processed foods tend to be easy to digest, highly palatable, and calorie-dense, while fiber slows digestion and helps regulate the metabolic response to food.

3. The Mediterranean diet: the best-supported dietary pattern.

Of all the dietary patterns Topol discusses, the Mediterranean diet has perhaps the strongest overall evidence behind it.

It emphasizes:

• olive oil

• vegetables

• fruits

• legumes

• whole grains

• nuts

• fish and seafood

while reducing red and processed meat, sweets, and highly processed foods.

Evidence from large observational studies and several randomized trials—including the PREDIMED trial and the Lyon Heart Study—has associated the Mediterranean diet with lower risks of cardiovascular disease, diabetes, cancer, neurodegenerative disease, and overall mortality.

In older adults, a Mediterranean diet has also been shown to favorably affect the gut microbiome, reduce inflammation and frailty, and potentially support cognitive function.

Topol even discusses a “green Mediterranean” diet, which adds more plant-based foods while further reducing meat. A small randomized trial found improvements in LDL cholesterol, inflammation, blood pressure, and weight, although it was too small to establish long-term health outcomes.

So far, however, Topol doesn't claim that we have found a diet that is definitively better than the Mediterranean diet.

4. Taurine: promising, but not proven.

Taurine is an interesting example of how longevity research can move beyond established dietary advice.

Taurine levels appear to decline with age, and lower levels have been associated with diabetes, hypertension, abdominal obesity, and inflammation.

Animal studies are particularly intriguing. Taurine supplementation has been associated with improvements in mitochondrial function, DNA damage, inflammation, cellular senescence, and other markers of aging.

In aged rhesus monkeys, six months of taurine supplementation produced several promising improvements in health markers, including fasting glucose, bone density, and markers of mitochondrial, liver, and immune function.

Taurine-rich foods include shellfish, dark poultry meat, milk, yogurt, cheese, and peanuts. It is found in very few plant foods.

But an important caveat:

Promising animal research ≠ proven anti-aging treatment in humans.

We don't yet have randomized human trials demonstrating that taurine supplements extend healthspan.

5. Choline: important for the brain.

Choline is an essential nutrient involved in several important brain functions.

Good food sources include:

• egg yolks

• fish

• meat

• milk

• soybeans

• mushrooms

• broccoli and other cruciferous vegetables

The recommended daily intake is about 550 mg for men and 425 mg for women.

For most people eating a varied, whole-food diet, getting enough choline shouldn't be particularly difficult.

There are some intriguing findings suggesting that higher choline intake or supplementation may benefit cognitive function in older adults. But once again, Topol emphasizes that randomized trials are needed before we can draw firm conclusions.

The bigger picture

Healthy aging is about establishing a dietary pattern that consistently gives the body the right inputs.

Eat more:

vegetables, fruits, legumes, whole grains, nuts, seeds, olive oil, and fish. Get plenty of fiber.

Eat less:

ultra-processed food, added sugar, sugary drinks, processed meat, and excessive alcohol.

And don't become obsessed with any single nutrient while ignoring the quality of the overall diet.

Don't ask only, “How many calories, grams of protein, or grams of fat am I eating?” Ask, “What kind of food am I putting into my body?”

For healthy aging, food quality and overall dietary pattern may matter more than chasing nutritional extremes.

8/18/2026

This is the fifth piece in my series about Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity.

Let's see what he has to say about caffeine, alcohol, red meat, and plant-based diets.

Caffeine

There are five main points Topol makes about caffeine and coffee.

1. Coffee consumption is associated with lower mortality

This is the headline finding. Large observational studies have found that coffee drinkers tend to have lower all-cause mortality, with some studies reporting reductions of around 30%.

The apparent benefit seems to peak at around four cups a day, rather than continuing to increase indefinitely.

2. Coffee is associated with a lower risk of several diseases

Across hundreds of studies, coffee and caffeine consumption have been associated with lower risks of:

• cardiovascular disease

• heart failure

• type 2 diabetes

• Parkinson's disease

• breast cancer

• colon cancer

• endometrial cancer

• prostate cancer

That's an impressive list.

But Topol is careful about the word “associated.” Most of these are observational studies. Coffee drinkers may differ from non-coffee drinkers in other ways, including exercise, diet, smoking, socioeconomic status, and other lifestyle factors. So, as always:

Correlation does not establish causation.

3. The old fear that coffee causes dangerous heart rhythms appears overstated

For decades, people with heart problems were often warned to avoid coffee because caffeine was thought to increase the risk of arrhythmias. But newer evidence does not support such a broad warning.

Large studies have found no higher overall risk of arrhythmias among coffee drinkers, and some studies have actually found a lower risk.

Topol's practical conclusion is that, for most people, coffee does not appear to pose the cardiovascular danger that was once widely assumed.

4. Decaf coffee may also have benefits

Some of the favorable associations have also been observed with decaffeinated coffee.

That suggests caffeine may not be the only—or even necessarily the main—reason coffee might be beneficial.

Coffee contains hundreds of compounds, including polyphenols such as chlorogenic acid.

Topol mentions several possible mechanisms, including:

• antioxidant effects

• improved insulin sensitivity

• reduced inflammation

• favorable changes in the gut microbiome

• effects on brown adipose tissue

• possible effects on DNA repair

But he emphasizes that none of these explanations has been established as the definitive mechanism.

5. The big caveat: we still don't know whether coffee itself causes the benefit

Topol is enthusiastic about the evidence, but he doesn't overstate it.

The overall evidence is reassuring and potentially quite encouraging, but we still don't have unequivocal proof that coffee itself causes people to live longer or become healthier.

Alcohol

The evidence surrounding alcohol is much less favorable than the evidence surrounding coffee.

1. The supposed health benefits of moderate alcohol consumption are highly questionable

The long-standing belief that moderate drinking—particularly red wine—is good for the heart has been seriously challenged.

The famous “French paradox” does not establish that wine itself protects against cardiovascular disease.

2. Alcohol is a known carcinogen

Alcoholic beverages are classified as carcinogenic to humans.

There is particularly strong evidence linking alcohol consumption to cancers of the oral cavity and esophagus, along with several other cancers.

Several countries are therefore moving toward stronger health warnings on alcohol products.

3. Very light drinking appears to carry relatively little risk, but risk rises with consumption

Some studies produce a J-shaped curve, in which very light alcohol consumption is associated with slightly lower observed risk, followed by rapidly increasing risk at higher levels of consumption.

But Topol does not interpret this as proof that alcohol is beneficial.

4. Alcohol increases blood pressure and cardiovascular risk

There is a dose-response relationship between alcohol consumption and hypertension.

Topol also cites Mendelian-randomization research supporting a causal relationship between alcohol consumption and certain cardiovascular diseases.

As consumption increases, the risks become substantially greater.

5. Overall conclusion

The message is much clearer and more negative than his discussion of coffee:

Alcohol is not a health-promoting substance. If someone enjoys an occasional drink, very light consumption may carry relatively little risk, but there is no good reason to drink for health benefits, and the risks rise quickly as consumption increases.

Red Meat and Plant-Based Diets

Topol places red meat and plant-based foods at almost opposite ends of the spectrum—not only in terms of potential health effects, but also in terms of environmental impact.

1. Processed meat is the biggest concern

Processed meats such as bacon, hot dogs, and sausages are classified by the World Health Organization's cancer agency as carcinogenic and are associated with increased cancer and mortality risks.

Their production also has a substantial environmental impact.

Unprocessed red meat, particularly beef and pork, is classified as “probably carcinogenic” and has also been associated with higher mortality risk.

2. But the evidence deserves some caution

This is an important qualification.

Systematic reviews involving nearly 120 studies found an increased cancer risk associated with processed and unprocessed red meat, but concluded that the absolute increase was small and the certainty of the evidence was low.

The evidence concerning cardiometabolic outcomes is similarly unsettled.

A large U.S. cohort followed for 19 years found small increases in all-cause mortality associated with both processed and unprocessed meat, but not with fish or poultry. Another analysis found that consuming two or more servings of meat or poultry was associated with a modest 4–7% increase in cardiovascular-disease risk.

So Topol's argument is that the long-term evidence consistently points in an unfavorable direction as red-meat consumption increases, particularly for processed meat.

3. Whole-food plant-based diets show a much more favorable pattern

Multiple large studies have found associations between plant-centered diets and better health outcomes:

• A pooled analysis of nine studies involving more than 300,000 participants found a 23% lower risk of type 2 diabetes among people following plant-based diets.

• A meta-analysis of 32 studies found that replacing processed meat with plant foods was associated with lower all-cause mortality, cardiovascular mortality, and type 2 diabetes.

• Among more than 72,000 people in Japan, greater plant-protein intake was associated with an 11% lower risk of total and cardiovascular mortality.

• Replacing just 3% of calories from animal protein with plant protein was associated with a substantially lower risk of cancer mortality.

• A randomized trial involving identical twins found that a plant-based diet slowed the pace of biological aging based on DNA-methylation markers compared with an omnivorous diet.

The important distinction here is whole plant foods: vegetables, fruits, beans, lentils, nuts, seeds, and whole grains.

4. “Plant-based” does not automatically mean healthy

This is another important caveat.

Commercial plant-based meat substitutes are not necessarily equivalent to whole plant foods.

Some can be:

• high in sodium

• relatively high in saturated fat

• highly processed

• nutritionally quite different from beans, lentils, and other whole plant protein sources

Topol also raises questions about heme iron in some products and notes that long-term human evidence on these newer meat alternatives remains limited.

So:

A lentil-and-vegetable meal and a highly processed plant-based burger may both be called “plant-based,” but they are not nutritionally equivalent.

The Bottom Line

Topol's overall message is fairly straightforward:

The more red meat you eat, especially processed red meat, the less favorable your health profile is likely to be.

At the same time, the evidence for whole plant foods and plant-centered diets is considerably more encouraging.

Perhaps the simplest way to put it is:

Eat more of what comes from the ground, less of what comes from a factory, and don't expect any single food or nutrient to be a magic bullet for longevity.

8/17/2026

This is the fourth piece in my series about Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity.

There is so much to talk about in this book. In this chapter, Topol takes a close look at some of the most basic components of our diet: sweeteners, salt, carbohydrates, protein, and fat.

What I find particularly interesting is that he doesn't simply label one nutrient “good” and another “bad.” Again and again, he emphasizes that the amount matters, but so does the type and quality of what we consume.

Sweeteners

The evidence linking sugar-sweetened beverages to poor health outcomes is particularly consistent. Topol cites studies associating high consumption with higher all-cause mortality, cardiovascular mortality, cancer mortality, increased atrial fibrillation, and dental disease.

One reason is obvious: sugary drinks can deliver a large amount of rapidly absorbed sugar without making us feel particularly full.

Topol is much more cautious about artificial and non-nutritive sweeteners. The evidence is mixed. Some studies have found little compelling evidence of harm, while others suggest that certain sweeteners may affect glucose regulation or alter the gut microbiome.

His overall conclusion is that artificial sweeteners appear less concerning than large amounts of sugar, but they should not automatically be regarded as completely harmless.

For ordinary people, the practical advice is simple:

Best choices: water, unsweetened tea, unsweetened coffee, and whole fruit.

Occasionally having a sweetened drink is one thing, but don't make it a regular part of your life.

Perhaps the deeper lesson is to gradually train ourselves to need less sweetness altogether.

Salt

Topol's discussion of salt is more nuanced than simply saying, “The less, the better.”

1. Too much sodium is a problem.

The relationship between high sodium intake and hypertension is well established, although the size of the effect varies considerably from person to person.

2. Don't blindly pursue “the lower, the better.”

Different health organizations recommend somewhat different sodium limits, and the evidence doesn't support the idea that reducing sodium indefinitely will produce proportionally greater benefits.

Topol notes that moderate sodium intake is not necessarily a problem, while very high intake is much more clearly associated with cardiovascular risk.

3. Sodium may affect more than blood pressure.

Topol also discusses evidence that excessive sodium may impair blood flow to the brain through dysfunction of the blood-vessel lining, potentially affecting cognitive health.

4. Moderation is more realistic than a miserable diet.

His practical suggestions include:

• Don't routinely add salt to food.

• Pay attention to sodium on food labels.

• If you have hypertension, be particularly careful about sodium.

• If you don't have kidney disease, consider a potassium-chloride salt substitute.

• Don't turn healthy eating into an intolerable, flavorless diet.

In other words, the goal is sensible reduction, not eliminating salt from your life.

Carbohydrates

Topol introduces the term “carbotoxicity” to describe the potential harms associated with excessive carbohydrate consumption.

His message is both very low carbohydrate intake—less than about 40% of total calories—and very high intake—more than about 70%—have been associated with increased all-cause mortality.

The more important question is:

What kind of carbohydrates are you eating?

Good carbohydrates

Topol gives priority to:

• non-starchy vegetables

• legumes

• fruits

• whole grains

• resistant starch

• other high-fiber, minimally processed foods

He cites a large body of research involving 185 prospective studies and 58 randomized trials showing that consuming roughly 25–30 grams of dietary fiber per day was associated with substantially lower risks of cardiovascular disease, type 2 diabetes, colorectal cancer, and all-cause mortality.

Poor-quality carbohydrates

These include:

• added sugars

• refined grains

• rapidly digested starches

• highly processed potato products

• foods with a high glycemic load

These foods can cause rapid rises in blood glucose and insulin and are associated with weight gain and poorer cardiovascular outcomes.

So once again, the message:

“Eat better carbs.”

Protein

The standard protein RDA of 0.8 grams per kilogram of body weight per day may not adequately reflect the needs of seniors. Much of the evidence behind that recommendation came from relatively short-term studies involving younger adults.

Because sarcopenia—the age-related loss of muscle mass and strength—is one of the major threats to healthspan.

Topol argues that older adults probably need more protein than the basic RDA, although the optimal amount remains uncertain. He considers increasing intake to around 1.2 g/kg/day reasonable.

But he also warns against assuming that more protein is always better.

Very high protein intake—particularly above about 1.5 g/kg/day—has been associated in some research with potentially unfavorable effects, including changes in the gut microbiome and production of pro-inflammatory metabolites. He also discusses concerns about leucine-rich animal proteins and pathways related to atherosclerosis and cellular waste disposal.

However, this is an area where Topol acknowledges significant uncertainty.

We don't yet have the kind of long-term, large-scale randomized trials that could definitively tell us exactly how much protein older adults should consume to maximize healthspan and prevent sarcopenia.

There's another interesting limitation: food labels don't tell us how much of each essential amino acid a food contains. So consumers can't easily compare foods based on amino acids such as leucine, lysine, or methionine.

The practical message I take from this section is:

Older adults should pay attention to getting enough protein to preserve muscle, but don't assume that an extremely high-protein diet is automatically healthier.

Fat

Fat is another example of why nutrition isn't as simple as “avoid fat.”

Topol explains that fat activates a gut-brain reward pathway involving the vagus nerve. This pathway can work together with the brain's sugar-reward pathway to increase dopamine signaling and encourage overeating.

That helps explain why combinations of fat + sugar can be so difficult to resist.

These foods combine multiple powerful reward signals while packing a lot of calories into a relatively small amount of food:

• ice cream

• pastries

• donuts

• cookies

• chocolate

• many packaged desserts

Fat quality matters

Topol also emphasizes that the type of fat matters.

Replacing saturated fats with mono- and polyunsaturated fats, particularly plant-based unsaturated fats, has been associated with more favorable cardiovascular and metabolic outcomes.

This is another reason not to think simply in terms of “high-fat” versus “low-fat.”

A handful of nuts, olive oil, or avocado is very different from a highly processed food loaded with saturated fat.

What about the ketogenic diet?

Topol is skeptical of the popular ketogenic diet, which is extremely high in fat and very low in carbohydrates.

He cites research associating ketogenic diets with potential problems including:

• higher cholesterol

• cardiovascular risk

• “keto flu”

• brain fog

• fatty liver

He also discusses a randomized NIH study comparing a ketogenic diet with a plant-based, low-fat diet. Interestingly, participants on the ketogenic diet consumed about 700 more calories per day during the two-week study, and the low-fat group lost more weight.

That finding challenges the idea that simply lowering carbohydrates and insulin will necessarily reduce hunger and food intake.

So what is the big picture?

I think Topol's message can be summarized in one sentence:

On carbohydrates, protein, or fat; pay attention to their quality, their source, and the amount you consume.

All three macronutrients are necessary. They can also contribute to health problems when consumed in inappropriate forms or excessive amounts.

In summary:

Carbohydrates: choose fiber-rich, minimally processed sources.

Protein: get enough to preserve muscle as you age, but don't assume extremely high intake is better.

Fat: favor unsaturated fats and pay attention to the powerful combination of fat and sugar in highly palatable foods.

Sugar: particularly avoid making sugary beverages a regular habit.

Salt: reduce excessive intake without turning healthy eating into an unsustainable low-sodium diet.