Featured research · Isaiah 58 · 2020
The power of fasting—researched by Dr. Anne Tanner, our new Director of Research & Analytics.
Isaiah 58 opens with a complaint you could have heard in April 2020. “Wherefore have we fasted, say they, and thou seest not?” (Isaiah 58:3). The people want to know whether their fasting did anything. The Lord answers by describing the fast He chooses, and then He makes a promise: “Then shall thy light break forth as the morning, and thine health shall spring forth speedily” (58:8). In the spring of 2020 a prophet who had spent his first career as a heart surgeon prescribed a fast for the whole world, for relief from a pandemic. Then, twelve days later, he prescribed it again. Seven months after that, a microbiologist woke up on a Sunday morning with an impression she couldn’t shake: go look at the numbers. Here is what she found, what it can and can’t tell us, and what Isaiah said to expect.
A heart surgeon called the world to fast. Twice.
Before he was a prophet, Russell M. Nelson was an internationally renowned surgeon and medical researcher. He helped develop the heart-lung machine that made open-heart surgery possible, and he spent decades with his hands inside the human heart. He knew what a body does in a crisis, how fast it happens, and when help can’t wait.
On Thursday, March 26, 2020, he posted a video. He opened as a doctor: “As a physician and surgeon, I have great admiration for medical professionals, scientists, and all who are working around the clock to curb the spread of COVID-19.” Then he invited members of the Church of Jesus Christ of Latter-day Saints “along with our many friends” to fast and pray on Sunday, March 29, “for relief from the physical, emotional, and economic effects of this global pandemic.”
That gave the world three days’ notice. Anne noticed it too:
“I honestly think the March 29th request for a worldwide fast maybe wasn’t as well advertised, and that’s why he … asked for it again with a little bit more lead time.”
Nine days later, on Saturday, April 4, during general conference, he asked again. A surgeon doesn’t call for help twice in two weeks unless the patient is still in danger. Worldwide fasts called by a prophet are rare. When he called the first, Church News could point to only three in the previous 35 years: two in 1985 for famine in Ethiopia, ten months apart, and one in 2005 after the Indian Ocean tsunami. He called two before the first one was two weeks old. “I thought [it] was interesting,” Anne said, “that President Nelson called for a second global fast so quickly.”
He called in haste. Isaiah 58 promises an answer in haste.
In that second call, during the Saturday evening session, he called fasting “an ancient doctrine practiced since the days of Moses, David, Esther, Isaiah, and Daniel,” and he quoted Isaiah 58:6 word for word: “to loose the bands of wickedness, to undo the heavy burdens, and to let the oppressed go free.” This time he named Good Friday, April 10, twelve days after the first: “I invite all, including those not of our faith, to fast and pray on Good Friday.” Leaders of other churches echoed the call. A Facebook group organized around the Good Friday fast grew past half a million members, people of every belief, all over the world. Afterward President Nelson said he was humbled “to learn of friends from many faiths all over the world who joined with us.”
President Nelson died in September 2025, at 101. The fasts he called are part of what he left us.
A scientist who couldn’t shake an impression
Dr. Anne Tanner has spent her whole career on the question underneath these charts: how microbes make us sick, and how to stop them.
In her words: “I have a bachelor’s in microbiology and then a PhD in microbiology and molecular biology, and I’ve worked a lot with things that can make us sick, like bacteria and viruses, and how they do it.” Both degrees are from BYU. She has worked hands-on with viruses, in HIV research and in phage therapy, which utilizes viruses that can infect and kill bacteria that antibiotics can no longer stop. She did that work first at a biotech startup and then at a medical school, where she still does it today. Reading infection data is not a hobby for her. It is her daily work.
When the pandemic came, she wasn’t an outsider looking in. She was a scientist looking at her own field. In her words:
“While I am a scientist by profession, my knowledge of God and His Son, Jesus Christ, are preeminent in my life and my heart. I remember Elder David A. Bednar teaching that our academic work is illuminated when we look at it through the eyes of the gospel, not the other way around. And I think of then Elder Russell M. Nelson at the BYU Life Sciences Building dedication when he said, ‘I think that a person can learn more by studying God’s creations than by studying the works of people, even by the most erudite and educated scholars.’ I acknowledge God as the Master Scientist and want Him to teach me the way things really work.”
In November 2020 she woke up on a Sunday morning with something on her mind she hadn’t considered before.
“There wasn’t really a lead up. I woke up one Sunday morning and this was really impressed on my mind that I needed to look at COVID data, and compare it with the worldwide fasts that we’ve had, the two of them … I hadn’t ever considered looking at it before. This was a strong impression.”
As she recorded in her journal that week:
“For the next 4 hours that morning I was totally immersed in looking at and making charts with case counts and death rates etc. and how they changed over the course of the pandemic. I was and have continued to be amazed at how the death rate was ramping way up and then how it completely turned around right at the fast.”
They pulled public data: weekly deaths and activity indicators from the Centers for Disease Control and Prevention (CDC), and case and death counts from the European Centre for Disease Prevention and Control and The New York Times, which were publishing downloadable datasets at the time. Her friend, Stacey Unck, built the charts. The two met in their ward during the pandemic, on walks, and have been friends ever since. “I was just the data visualizer,” Stacey told me. “Anne gave me the data, asked me questions, I created the charts and graphs.” Stacey spent five years at Tableau, one of the world’s leading data-visualization companies, where she built dashboards in its software to measure performance; the charts are built in Tableau too. In her own post that week she wrote, “If you know me, you know that I love data and I love faith.” They marked two vertical lines on every one of them: March 29 and April 10. Anne and Stacey posted the charts on November 20, 2020, the same week. Friends reposted them. As far as Anne knows, no one else has ever run the numbers this way: “I don’t know anyone who’s looked at it. It’s kind of an unusual thing to look at.”
November 20, 2020 was also the day President Nelson released a video message called The Healing Power of Gratitude. The surgeon-prophet reached for a doctor’s word: “may I prescribe two activities to help us experience the healing power of gratitude.” He called gratitude “a unique, fast-acting, and long-lasting spiritual prescription,” asked the world to fill social media with thanks for seven days under #GiveThanks, and offered a prayer of gratitude for the world and everyone in it. Stacey remembers that day. “I just assumed he was going to do it again,” she said, a third fast. Instead the prophet prayed with the world. “I thought you had set the standard of how we do this and we did the data and we found out that fasting worked and then he was like ‘that’s not the only way’ … God has many ways of healing the world and of doing his work and he’s trying to teach us those ways. One of them is the fast and the other is group prayer.”
He also told the story behind it: “A few weeks ago, I woke in the middle of the night with the thought that I should offer a prayer of gratitude to God for all of His children around the globe.”
A prophet woke with an impression. A scientist woke with one too. When Anne’s friends reshared her charts, they tagged them #givethanks.
Stacey draws her own lesson from the way it came together: “She needed my skills and I needed her ideas in order to come up with that. And so that was really powerful. … The Lord uses shared revelation to get his work done.”
When I asked Anne whether impressions like that happen to her often, she was careful:
“I’ll have an idea to try something specific on a project that I’m working on … that I myself wouldn’t consider or think about doing. But I’ll have kind of the thoughts of doing it, and I think those are impressions. … When I feel something like that, it generally works out, and I wouldn’t take credit for that. I would call it inspiration. … It’s not like a voice or anything, but just, I think a lot of the time thoughts are impressions.”
Part One · What the charts show
Read each chart the way Anne read it to me: find the two vertical lines, then watch what the curve does after them.
When Stacey first drew those two lines, the result startled them both: “We put those bars to show the weeks of the fasts and we like felt like we had doctored the data, because it was so very clear that the numbers went down, and specifically the number of deaths by week went down.”
U.S. deaths by week. The curve climbs almost straight up through March and keeps climbing straight through the first fast. It peaks in the week right after April 10. Then it turns, and keeps falling for two months. By the third week of June, weekly deaths were down about 78 percent from the peak. CDC’s final counts confirm it: 17,221 deaths in the peak week, ending April 18; 3,852 in the week ending June 20. A second, smaller wave follows in July.
“But on April 10th, you see the graph just takes a sharp turn down … so a pretty dramatic drop in deaths per week for the US.”
Global deaths by week. The same turn. Worldwide weekly deaths crest in the two weeks after April 10, then fall six weeks in a row. On Anne’s chart, built from European data, the drop is nearly half; in the World Health Organization’s count, it is about a third. Then they climb again, and by November they are higher than the April peak. Anne was the first to point that out, and she didn’t spin it: she wondered whether more countries simply began counting. “Is that because there’s more countries that started to report, keep track and report? I don’t know. There’s some confounding factors with that aspect that I’m not going to be able to probably figure out.”
U.S. activity indicators. This is the chart I’d study longest. It shows five measures. Two of them are early signals: the share of tests coming back positive, and the share of emergency visits for COVID-like illness. Both peak right at the March 29 line and fall from there. (One note on the first: commercial labs only began reporting enough tests for CDC to track their positive rate the week of March 29, so the earliest part of that line rests on fewer labs.) The share of deaths caused by pneumonia, influenza or COVID, a late signal, peaks just after April 10 and falls for two months.
Anne told me that on the death chart, at the first fast, “the number of deaths per week in the US continued to climb,” and she’s right. But deaths trail infections by weeks. On the early-signal chart, our reading is that the turn begins at the first fast and shows up in the deaths after the second. Draw your own conclusion; the lines are right there.
Cases and death rate. Known cases keep rising all year, in the U.S. and worldwide. But the death rate, the share of known cases that ended in death, peaks in the week after April 10 and falls for the rest of the year: in the U.S., from about 8 percent in April to under 1 percent by November, with a small rise in late summer. Wider testing explains part of that drop, because finding more mild cases lowers the rate. Anne said it plainly: “Even when the total number of new cases went up, again, is this because more people started tracking it? I can’t speak to that. The death rate still went down.”
Part Two · What a skeptic will say, and why it doesn’t scare us
Here is what anyone who knows epidemiology will say in the first ten seconds, so let’s say it first.
Forty-two states and the District of Columbia issued stay-at-home orders between March 19 and April 7, 2020. Infections slowed. Deaths, which trail infection by about three weeks, peaked in mid-April and fell. Testing expanded, which lowered the death rate on paper. And many countries were only starting to count. Every one of those things is true.
Anne knows all of this better than most. And she said this about her own result: “It’s dramatic. Like I said, I wouldn’t have believed it if I hadn’t have run it myself.”
None of them is a problem for faith.
A heart surgeon didn’t ask the world to choose between the doctors and the Lord. He opened his invitation by praising “all who are working around the clock to curb the spread” and in the same breath asked us to fast. Alma taught his son Helaman the pattern: “the Lord God doth work by means to bring about his great and eternal purposes; and by very small means the Lord doth confound the wise” (Alma 37:7). A fast and a stay-at-home order were never rivals. The Lord has never minded that we can see the means. What we are asked to notice is the timing, and whose hand is on it.
So this is the claim, and it is all the claim we need: the world fasted twice, and in the weeks that followed, the curves turned. The data shows the turn. What the turn means is between each of us and the Lord. Anne put it this way:
“So it was really cool to see how people coming together of all different faiths could make such a difference and to see the Lord’s mercy in His response.”
Stacey put it this way in her own post that November: “Even though numbers and anxieties are high again, I know that God is real, and he’s got us. Turn to him, show some sacrifice and he will do great things with your life.”
Part Three · The fast Isaiah said the Lord would answer
Go back to Isaiah 58. The people in verse 3 had fasted. They’d bowed their heads, put on sackcloth, gone without bread. And the Lord said He didn’t count it, because they fasted “for strife and debate” and kept driving their workers while they did it (58:3–4).
Then He describes the fast He chooses:
“Is not this the fast that I have chosen? to loose the bands of wickedness, to undo the heavy burdens, and to let the oppressed go free, and that ye break every yoke? Is it not to deal thy bread to the hungry, and that thou bring the poor that are cast out to thy house?” (Isaiah 58:6–7)
That is the verse President Nelson reached for in April 2020: undo the heavy burdens. The Lord’s fast is never only hunger. It’s hunger that turns outward, toward the sick, the poor, the one cut off. In the spring of 2020 a whole world turned outward at once, people of every faith, for strangers they would never meet.
And then come the promises, each one starting with then:
“Then shall thy light break forth as the morning, and thine health shall spring forth speedily … Then shalt thou call, and the LORD shall answer; thou shalt cry, and he shall say, Here I am.” (Isaiah 58:8–9)
The Hebrew word Isaiah uses for health is ʾărukah. It means the healing of a wound: the new flesh that grows back over an injury. Jeremiah uses the same word when the Lord promises, “I will restore health unto thee, and I will heal thee of thy wounds” (Jeremiah 30:17). Isaiah isn’t promising that nothing will hurt. He’s promising that what is wounded will close over and heal.
And notice how fast. The light doesn’t creep up; it breaks forth. The Hebrew verb, baqaʿ, means to split open, the way the dawn splits the dark in a single stroke. The health doesn’t come back slowly; it springs forth speedily, meherah, in haste. The surgeon-prophet called the world to fast in haste, twice in twelve days, because the need was urgent. Isaiah’s promise answers at the same speed. And on Anne’s charts, the turn didn’t wait for summer. It came in the very next week.
One more word in that verse. Spring forth is titsmach, from tsamach, to sprout. It is the root of Tsemach, “the Branch,” one of the Messiah’s titles: “In that day shall the branch of the LORD be beautiful and glorious” (Isaiah 4:2); “I will raise unto David a righteous Branch” (Jeremiah 23:5). The health Isaiah promises sprouts from the same root as the name of the One who heals.
Stacey has lived the personal side of those promises. A couple of years after the charts, she asked the Lord the rich young man’s question, what lack I yet?, and the answer she felt was to fast more often. Later, listening to a talk on the promises that come with fasting, she turned to Anne:
“I know that’s true. That has been my life. I’m kinder, more patient … I’m not all the things I need to be, but I’m much more than I used to be as a result of fasting. I have had the personal benefits of fasting in addition to being an eyewitness to the data behind the benefits of the worldwide fasts.”
And the last promise is the one that matters most. Not the numbers will fall, but “he shall say, Here I am.” The point of the fast is not the chart. It is the Person who answers.
Your turn
You don’t need a PhD to do what Anne did. You need a question, a record, and the willingness to look.
- Read Isaiah 58 before your next fast. Read the whole chapter the night before, and notice how much of it is about other people.
- Fast outward. Pray for someone specific. Give a generous fast offering. Bring someone in from the edge.
- Keep a record. Write down what you asked for and when. Then watch. The searching is the meaning.
A witness
The data is too unbelievable not to check it, and check it again. We did. It holds.
But I didn’t need a chart to know the Lord answers a fast. At seventeen, at the Naval Academy, I fasted for three days. Twice. In an upper attic, the answer came: a new heart. And that new heart I gave back to Him. He gave me a second chance. He has my heart to this day.
An honest heart. A broken heart. A new heart. Now I’m seeking the pure heart, and waiting on the greatest promise of all: “Blessed are all the pure in heart, for they shall see God” (3 Nephi 12:8).
The One who answers the fast is Jesus Christ, and every answer He gives is carrying us, healed, home to His Father.
— Ken Krogue, SearchIsaiah.org
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