You Lost the Weight. Did You Fix the Metabolic Problem?

Editorial Transparency: HormoneSynergy® has no financial relationship with the PREVIEW investigators or the publications discussed here. This article is an independent review of published research for educational purposes and is not individualized medical advice.

A Good Study, and a Headline That Went Too Far

The claim circulating online was striking: nearly nine out of ten people who reverse prediabetes supposedly relapse within three years. The explanation was equally dramatic. Weight loss was described as little more than a proxy, while liver insulin sensitivity was presented as the factor that really determined whether remission lasted.

There is an important study behind that argument, but the numbers do not support the headline.

The 2026 analysis came from PREVIEW, a large multinational diabetes-prevention trial involving adults with prediabetes and overweight or obesity. Participants began with an eight-week rapid weight-loss phase before continuing into a longer lifestyle intervention.

For this post-hoc analysis, researchers had adequate three-year data on 846 participants. They classified 102 as remission maintainers, 126 as people who achieved remission at year one but later relapsed, and 618 as people who did not achieve remission.

The frequently repeated 12% figure comes from dividing the 102 maintainers by all 846 participants in the analysis. It does not represent the percentage of people who achieved remission and then managed to maintain it.

Among the 228 participants who had reached remission at year one, 102 remained in remission and 126 relapsed. The relapse rate among initial remitters was therefore approximately 55%.

That is still clinically important. It is simply very different from saying that nearly nine out of ten people relapse.

The Scale Still Mattered

The second problem with the online interpretation is the suggestion that the people who remained in remission were not necessarily the ones who maintained greater weight loss.

In the PREVIEW analysis, they were.

Participants who maintained remission had greater reductions in body weight and fat mass than those who relapsed. Compared with participants who never achieved remission, maintainers were approximately four kilograms lighter at three years after adjustment for baseline differences.

Weight loss was therefore not incidental to the findings. The study does not replace the familiar idea that weight matters with a new claim that weight does not matter.

What it does suggest is that weight loss and metabolic improvement should not be treated as interchangeable outcomes. They often move together, but not always to the same degree.

Where the PREVIEW Findings Become More Interesting

Researchers followed several measures related to insulin resistance over the three-year intervention. Participants who maintained remission continued to show more favorable fasting insulin levels and insulin-sensitivity indices. In contrast, people who relapsed gradually moved back toward a more insulin-resistant pattern during years two and three.

Those differences remained even after the researchers statistically adjusted for changes in body weight.

For clinicians, that may be the most useful part of the study. Two people can lose a similar amount of weight and still end up with different metabolic outcomes. One may show substantial improvement in insulin sensitivity, triglycerides, visceral adiposity and glucose regulation. Another may lose weight while retaining more of the underlying metabolic dysfunction that placed them at risk in the first place.

A bathroom scale cannot distinguish between those two situations.

Did PREVIEW Prove That the Liver Determines Remission?

No. That interpretation goes beyond what was measured.

The paper discusses hepatic insulin sensitivity, but investigators did not directly measure hepatic glucose production with isotope tracers, nor did they use a gold-standard clamp designed specifically to quantify hepatic insulin resistance.

Instead, the analysis relied on fasting insulin and calculated surrogate measures including HOMA-IR, QUICKI and the triglyceride-glucose index.

These measures are useful in both clinical research and practice. Because fasting glucose and insulin are influenced substantially by hepatic glucose regulation, they can provide insight into aspects of hepatic insulin resistance. They are not the same as directly measuring glucose production by the liver.

That distinction is important. Saying that people who maintained remission also maintained more favorable insulin-resistance markers is supported by the study. Saying that the liver was proven to be the mechanism responsible for sustained remission is not.

Prediabetes Is More Than a Glucose Number

This is where PREVIEW becomes particularly relevant to preventive longevity medicine.

Prediabetes is usually recognized when fasting glucose, HbA1c or another glucose measure crosses a diagnostic threshold. The metabolic changes that eventually produce that result may have been developing for years before the laboratory value became abnormal.

Insulin resistance can progress while fasting glucose still appears acceptable because the pancreas compensates by producing more insulin. Glucose begins to rise when that compensation becomes less effective.

That is why we do not think glucose should be interpreted in isolation. Fasting insulin, triglycerides, waist circumference, body composition, blood pressure and other metabolic markers can provide context that a glucose value alone cannot.

For a broader discussion, see Insulin Resistance Explained: Metabolic Health and Longevity.

Visceral Fat Makes the Scale Even Less Informative

A separate study published in Nature Medicine in 2025 approached the question from another direction by looking at people with prediabetes who achieved remission without losing weight.

Some participants returned to normal glucose regulation even though their overall body weight remained stable or increased. Their physiology, however, was not unchanged.

Those who achieved remission showed better insulin sensitivity and beta-cell function. Fat distribution also differed between the groups. Participants who did not achieve remission tended to accumulate more visceral adipose tissue, while those who achieved remission stored relatively more fat in subcutaneous depots.

The investigators reproduced key findings using data from the U.S. Diabetes Prevention Program.

None of this suggests that gaining weight should be a goal. It demonstrates something much more basic: total body weight cannot tell us where fat is being stored, how much visceral fat is present, or how much of a person's weight represents lean tissue.

A 175-pound body is not a diagnosis.

Why This Matters in the GLP-1 Era

Modern GLP-1 medications can produce reductions in body weight that were difficult to achieve consistently with lifestyle intervention alone. That has changed obesity and metabolic medicine in important ways.

It has also made the distinction between weight loss and metabolic health more important.

If a patient loses 30 pounds, that is an accomplishment worth recognizing. It is not unreasonable to ask what happened metabolically during the same period.

How much visceral fat was lost? Was skeletal muscle preserved? What happened to fasting insulin and triglycerides? Has glucose regulation improved? Did blood pressure change? Is the patient stronger and more physically capable than before?

These questions do not diminish the value of weight loss. They put the weight loss into context.

Why Body Composition Matters

Traditional weight and BMI tell us very little about visceral fat or lean mass. That limitation becomes increasingly important with aging, aggressive calorie restriction and GLP-1 treatment.

At HormoneSynergy®, body composition is part of the larger metabolic picture because losing skeletal muscle in pursuit of a lower number on the scale is not the outcome we are looking for.

DEXA can quantify total and regional body composition, including visceral adipose tissue. Serial body-composition measurements can also help determine whether weight loss is coming primarily from fat or whether clinically important lean tissue is being lost along the way.

The same principle applies to the broader HormoneSynergy® Optimal Aging Assessment. A measurement is most useful when it improves our understanding of risk and influences what happens next.

What Should We Follow After Prediabetes Improves?

If someone's HbA1c returns to the normal range, that is good news. It does not necessarily mean the underlying metabolic problem has disappeared.

We would still want to know whether fasting insulin remains elevated, whether visceral adiposity has improved, whether triglycerides and blood pressure are moving in a favorable direction, and whether those changes persist after the initial period of intensive weight loss.

This is one of the reasons the PREVIEW analysis is useful. It did not stop at the point when participants crossed back into a normal glucose range. Researchers continued to follow them. Some remained in remission, while others gradually drifted back toward insulin resistance and prediabetes during the following two years.

There is an important difference between reaching a laboratory target once and changing the longer-term trajectory of metabolic disease.

The HormoneSynergy® Perspective

Weight matters. For many people with excess visceral adiposity and insulin resistance, reducing excess body fat is one of the most effective ways to improve metabolic health. PREVIEW itself reinforces that point because the people who maintained remission lost more weight and fat than those who relapsed.

The mistake is treating the scale as though it tells us the rest of the story.

After weight loss, we still want to know whether the physiology that created the risk has changed. That means looking beyond pounds and BMI to glucose regulation, insulin sensitivity, visceral fat, skeletal muscle, blood pressure, lipids, physical activity and the other factors that shape long-term metabolic health.

Prediabetes remission should be more meaningful than briefly moving a laboratory value from one side of a diagnostic threshold to the other. The goal is durable metabolic improvement.

That distinction is central to What Actually Moves Longevity Metrics.

Medicine, Not Marketing.

Frequently Asked Questions

Did 9 out of 10 people in the PREVIEW study relapse after reversing prediabetes?

No. The analysis included 846 participants. Of those, 102 maintained remission, 126 achieved remission at year one and later relapsed, and 618 did not achieve remission. Among the 228 participants who initially achieved remission, approximately 55% later relapsed.

Does weight loss reverse prediabetes?

Weight loss can substantially improve glucose regulation and insulin sensitivity and remains an important strategy for many people with prediabetes and excess body fat. It does not guarantee durable remission, and research also shows that some people can improve glucose regulation without substantial changes in total body weight.

Did the PREVIEW study prove that liver insulin resistance causes prediabetes relapse?

No. This was a post-hoc observational analysis within a randomized lifestyle trial. Researchers assessed insulin resistance using surrogate measures rather than directly measuring hepatic glucose production. The findings support an association between sustained insulin sensitivity and sustained remission, but they do not establish that hepatic insulin resistance alone causes relapse.

Why can someone improve metabolically without losing much weight?

Total body weight does not show where fat is stored, how much visceral adipose tissue is present or how insulin sensitive a person is. Changes in visceral and subcutaneous fat distribution, insulin sensitivity and beta-cell function can influence glucose regulation even when overall body weight changes relatively little.

What should be monitored after prediabetes improves?

Follow-up should be individualized but may include fasting glucose, HbA1c, fasting insulin, triglycerides, blood pressure, waist circumference, visceral fat, body composition, physical activity and other cardiometabolic risk markers. The purpose is not simply to document that glucose improved once, but to determine whether the broader metabolic improvement is being maintained.

Selected References

Zhu R, Guo J, Huttunen-Lenz M, et al. Enduring improvements in hepatic insulin sensitivity predict sustained remission of prediabetes during a 3-year lifestyle intervention: results from the PREVIEW multinational diabetes prevention trial. Metabolism. 2026;178:156546. doi:10.1016/j.metabol.2026.156546.

Sandforth A, et al. Prevention of type 2 diabetes through prediabetes remission without weight loss. Nature Medicine. 2025. Nature Medicine.