How Not to Diet

by Michael Greger

Study subjects eating a specified snack at 10:00 a.m. burned about six more grams of fat from their bodies than on the days they ate the same snack at 11:00 p.m.2894

A study of more than one hundred thousand women controlled for this and found that the odds of obesity trended with higher nighttime light exposure independent of sleep duration.2913 Compared to women who reported their bedrooms at night were either too dark to see their hands in front of their faces or at least too dark to see across the room, those who reported it was light enough to see across their bedrooms were significantly heavier on average.

the doses found in melatonin supplements are massive. Even just taking a 3 mg dose produces levels in the bloodstream that can be fifty times higher than normal nightly levels,2940 which raises safety concerns.

After all, melatonin used to be known as an anti-gonad hormone, with human-equivalent doses of just a milligram or two reducing the size of sex organs and impairing fertility in laboratory animals.

considering the pronounced effects of melatonin on reproduction in other mammals, commentators have suggested it might be naïve to assume melatonin wouldn’t have some effects on human sexuality. Some have even speculated it may have a role one day as some sort of a contraceptive agent.2943

Cranberries appear to be the most melatonin-rich fruit.2954 Consume just a single ounce, about a third of a cup, and it’s like you took a melatonin supplement with only good side effects.

Pistachios are not just the most melatonin-rich nut, they are off the charts as the most melatonin-rich food ever recorded.2957 To get a physiological dose of melatonin, all you have to eat is two. Two cups? Two handfuls? No, just two pistachios. Pistachio nuts were found to contain 0.2 mg of melatonin per gram.2958 It only takes 0.3 mg of melatonin to cause the normal daily spike our brains give us, so just two nuts would presumably do the trick.2959

Sleep during the night and be active during the day Sleep enough (seven to eight hours a night) Early to bed, early to rise Avoid bright light exposure at night Sleep in total darkness when possible Eat dinner at least two and a half hours before going to bed Avoid eating at night

It turns out that the study did include just such a third group, and the participants felt just as full sipping the smoothie with a spoon as they did eating the whole fruit—so the answer is time.2975 The only real reason smoothies aren’t as filling is that we gulp them down. If we sip them slowly over time, they can be just as filling as if we had eaten the fruits and veggies whole.

People were given soup, but half were given small spoons and told to eat slowly, and the other half were given big spoons and told to eat quickly, and an amazing thing happened: The slow-eating group not only ended up feeling more satiated, but they did so after eating less soup.2977 They felt fuller eating less food.

the mismatch between the sweetness on the tongue and the lack of calories flooding in when drinking diet soda may actually help explain some of the metabolic disruption associated with the consumption of artificial sweeteners.3006

Most people suffer gas and bloating at ten grams of sorbitol a day, which is about eight sticks of sorbitol-sweetened gum, and at twenty grams, most get cramps and diarrhea.3051 So be careful how much sorbitol you eat.

People overeat more liquid yogurt when presented with a straw versus a spoon because we can gulp faster than we can spoon.

Presented with thick or thin porridge, people feel just as satisfied eating about fifty fewer calories of the thick porridge.3059 So, when making oatmeal, remember that thicker and chewier may be more filling.

choose foods that take longer to eat, and eat them in a way that prolongs the time they stay in your mouth. Think bulkier, harder, chewier foods, such as apples, carrots, or intact grains, eaten in smaller, thoroughly chewed bites. Snack on raw veggies, and fall in love with soup. If possible, extend meal duration so it lasts at least twenty minutes to allow your natural satiety signals to take full effect.

make your smoothies thicker and sip them leisurely through a skinnier straw (preferably reusable, like the glass straws with silicone tips I love).

This is all the more reason to choose activities that are enjoyable, such as walking with friends or while listening to music or a podcast, or watching a video while on the treadmill. Reframing exercise as play rather than work may not only make for a more sustainable regimen, it may make us less likely to consciously or unconsciously feel the need to reward ourselves later at the buffet line.

The secret to weight loss through exercise may be sheer volume: at least three hundred minutes a week to achieve appreciable fat loss.3119

You don’t have to go full horse-and-buggy to enjoy the benefits of nonexercise activity thermogenesis. NEAT means taking the stairs instead of the escalator and parking at the far end of the lot. It means singing, laughing, cleaning, and doing yard work—any activity that creates muscular contractions. Cooking dinner burns five to ten times more calories than sitting in front of the TV.3179

In How Not to Die, I documented the health risks associated with prolonged sitting. The reason nearly all the studies to date on television viewing and mortality have found an association between screen-based entertainment and premature death is thought to be because screen time tends to equal sitting time.

What about standing versus sitting for weight loss? Standing burns three times more calories per minute than sitting.3185 Even if you’re standing still, your postural muscles are tensed and stretched to fight gravity,3186 so anything you usually do while sitting, try doing while standing, like watching TV or reading the newspaper.

In the short term, they were found to reduce sitting time at work on average by one hundred minutes per workday, but after three months, people appeared to tire of them and only sat about an hour less a day.3191 Those using sit-stand workstations were also found to compensate a bit at home by sitting down more in their off hours.3192

Walking at a treadmill desk, on the other hand, could wipe out more than seven hundred calories a day. Just moving at a snail’s pace at about one mile per hour, people burn an extra two calories a minute over sitting.3194 That means you could erase more than one hundred extra calories an hour while you work or two hundred extra calories at 3 mph.3195 (My treadmill desk is currently set at 1.8 mph.)

If you work 250 days a year and stroll while you work for even just half the workday, you could theoretically burn off thirty pounds of fat a year if your body didn’t otherwise compensate for the one hundred thousand annual calorie deficit.3196 No wonder obesity researchers have called for a “moratorium on the chair.”3197

Does productivity suffer using a standing or walking desk? With the exception of high-precision mouse tasks, work performance in general appears to be unaffected,3198 but one study of transcriptionists on treadmill desks found that their spe...

Sedentary comes from the Latin word meaning to sit, but just because you’re sitting doesn’t mean you’re sedentary—just ask any cyclist or rower. The problem is sitting motionlessly. That causes blood to pool and stagnate in our legs, which can result in arterial dysfunction. Just like our muscles can atrophy from disuse, it may be use it or lose it when it comes to artery function as well. Special cells lining our arteries can detect the tugging, sheer force of the blood flowing past and send signals through the artery wall to maintain proper structure and function.

If standing or dynamic workstations are not an option, taking five-minute walking breaks every hour can prevent the stiffening of the arteries that comes with prolonged sitting.3204 Frequent trips to the watercooler (and then subsequently to the restroom) or taking out the trash during commercial breaks can maintain full artery function.

Researchers concluded that “people should be encouraged to engage in aerobic leg exercise before sitting for extended periods of time and, if this is not possible, sitting should be replaced by standing.”3206

Walking briskly just fifteen minutes a day is associated with a life span gain of about two years, for example, and an hour a day may give us four more years on this earth.3216

HIIT participants accomplished in about an hour and a half a week what took the medium-intensity groups closer to two and a half hours—namely, no change in weight, but a loss of a few pounds of body fat over a few months and one inch off the waist.

This suggests that what matters is not the intensity but the total work performed3240—but that’s not entirely true.

Walking faster gets you there quicker, but you burn more—and that’s what we want. Efficiency is good for conserving energy, but if the aim is to lose weight, you don’t want to conserve your fat. You want to get rid of it.

in total, the runners beat out the walkers by about 50 calories and did so in half the time.3242

In a nutshell, continuous high-intensity activity beats out lower intensity, but shorts bursts of high intensity don’t appear to beat out continuous, moderate-intensity exercise.

the next day, before-breakfast exercisers woke up with about a quarter cup less fat after the same amount of exercise. Remarkable! Running for one hundred minutes is pretty hard-core no matter whether you do it before or after breakfast.

All such similar studies on both men and women show we burn through more fat on the days we exercise before, rather than after, eating.

When you work out before a meal, though, your muscles have to resort to dipping into your energy stores and end up burning mostly a combination of glycogen and fat.3258 That explains why you burn more fat during fasted exercise, but what about all the extra fat burned throughout the rest of the day?

Exercising before breakfast can exhaust as much as 18 percent of your glycogen stores, and that depletion can act as a powerful rallying cry to your fatty tissues to start pulling more of their weight by breaking down more fat. The lower glycogen stores fall, the greater the sustained twenty-four-hour fat loss.3260

How long do you have to go without food in order to trigger this effect? Six hours may be sufficient, so before breakfast isn’t the only optimal window.3261 If you timed it right, you could exercise midday before a late lunch or, if you had an early enough lunch, before dinner after you got home from work.

for those with blood sugar problems, it’s better to exercise after meals than before them. Blood sugar from a meal starts appearing in the bloodstream fifteen to twenty minutes after the first bite. It ramps up after thirty minutes to peak around the one-hour mark before declining to premeal levels within a few hours.

For optimal blood sugar control, prediabetics and diabetics should start exercising thirty minutes after the start of a meal and ideally go for an hour to completely straddle the blood sugar peak.

If you had to choose a single meal to exercise after, it would be dinner,3283 due to the circadian rhythm of blood sugar control that wanes throughout the day. Ideally, though, breakfast would be the largest meal of the day, and you’d exercise after that—or, even better, after every meal.3284

The first thing to recognize is that it is normal and natural to be physically lazy.3290 Laziness is in our genes. We evolved to instinctually avoid unnecessary exertion to conserve energy for survival and reproduction. These days, there’s no shortage of available fuel, yet the hardwired inertia remains.

Our ancient ancestors are presumed to have exercised only when it was necessary or when it was fun, as a form of play.

The only way exercise is going to work long term for weight control is if it becomes a stable, lifelong habit,3292 so you need to restructure your surroundings to require more physical activity (like working at a treadmill desk) and figure out how to make exercise more enjoyable.3293

Music has been described as a “legal method”3295 for improving peak performance and, more importantly, the enjoyment of high-intensity interval training.

During exercise, listening to a preferred playlist can significantly reduce our “rate of perceived exertion,” which is how hard you feel your body is working.

have them go until exhaustion with or without music, and those listening to their favorite tunes tended to make it about 5 percent longer. This was chalked up to “attentional distraction”—the music may have helped keep their minds off feelings of fatigue.3298 If that’s the case, listening to a podcast or audiobook may have a similar effect.

The recommendation to exercise sixty to ninety minutes for weight control has been dismissed as “too ambitious,”3299 “too daunting,”3300 and “too much, too soon,” fearing people will feel overwhelmed and not exercise at all.3301 In short, America, you can’t handle the truth.3302

Whose kids do you think consistently lost more weight? Did the stronger message overwhelm the moms into paralysis? No. Their kids lost nearly twice as much weight as the children whose mothers got the milder message.3303 Ignorance is less blissful when lives are on the line.