Top Things We’ve Learned About Healthy Weight Loss in 2024

Separating new insights from old myths about losing weight.

Reviewed by Davia Sills

Key points

• 2024 provided many important new health insights.
• Some of the most valuable health advancements in 2024 related to weight loss and metabolic health.
• New findings about nutrition, exercise, and sleep challenge many of our old beliefs.

2024 has been a breakthrough year for health. For example, this summer witnessed the first FDA approval for non-prescription continuous glucose monitors (CGMs were previously restricted by prescription to people living with diabetes). Virtual technology continued its accessibility transformation of mental healthcare, with data indicating that over half of mental health visits in 2024 were conducted using remote technology platforms. And advancements in stem cell technology even made the first medical reversal of type 1 diabetes possible this year¹.

Yet some of the most useful health insights we gained this past year concerned one of society's most urgent and widespread problems: metabolic and weight-related health conditions. Here are some of the most valuable scientific takeaways in this area from the past year.

1. New medicines help clarify how we lose weight.

When the investigators of the powerful new medicines, Wegovy and Zepbound, were initially trialing their effects for weight loss years ago, the prevailing theory was that these medicines primarily worked by increasing satiety hormones in the stomach, such as GLP-1 (Glucagon-Like Peptide-1). Fast-forward to 2024, and researchers now realize that much—for many people, even most—of the weight loss benefit comes from medicine-induced changes in brain regions that regulate food reward and satiety². These medicines are so effective because they modify both the physical and psychological circuits involved in eating.

2. Ultra-processed foods may be the primary cause of the obesity and diabetes epidemics.

According to international data collected by the World Health Organization, in the mid-1970s, every age, sex, and race group in the U.S. suddenly began increasing in obesity rates. Since then, we've blamed fats, blamed willpower, and blamed carbohydrates—especially sugar. Yet the highest-quality nutrition studies—precisely tracking eating and weight changes among people living in controlled metabolic laboratories—suggest that it is the ultra-processing of the food itself rather than the macronutrient content that leads to weight gain and health problems³.

Ultra-processing of food in the U.S. began in earnest in the '70s. It makes food hyper-palatable, calorie-dense, fiber- and nutrient-sparse and causes us to eat more. This combination appears to be a metabolic disaster for adults and children alike.

3. Exercise doesn't burn more calories; it redistributes energy use in healthy ways.

This finding might be the hardest for most people to believe. Yet some of the most rigorous metabolic studies conducted in humans over the past decade⁴ show that our bodies regulate energy expenditure just like they do body temperature, oxygen levels, and other homeostatic processes. This means that when we engage in exercise, rather than raising our overall metabolic rate, our body compensates partly by reducing energy expenditure for other body processes. This homeostatic model of energy expenditure probably explains why exercise studies show surprisingly modest weight loss for most people.

Yet, as discouraging as this might sound, there is a healthy silver lining. Metabolic studies show that regular exercise causes our body to reduce energy spent on other physiological functions—such as inflammation—that are core mechanisms of disease when present in excess.

In short, downregulating these energy sources is beneficial. It may be Mother Nature's genius that exercise is so good for our physical and mental health for reasons that are entirely different than we once thought⁵.

4. Nutrition and diet are as important for our mental health as for weight loss.

In 2017, results from studies such as the SMILES trial were among the first to demonstrate that dietary interventions could improve depression symptoms. The number of human clinical trials supporting the direct benefits of nutrition and exercise for mental health conditions has only compounded by 2024⁶.

We also understand many of the causal mechanisms enabling these mood benefits, such as reduced inflammation, improved mitochondrial function, greater insulin and leptin sensitivity, and other neurohormonal pathways that promote better brain function. Assisting people with nutrition, physical activity, and sleep may become a foundation for psychotherapy practice in the future.

5. Fiber is incredibly important to our metabolic health.

Fiber is now the unofficial "fourth macronutrient" (carbohydrates, fats, and proteins are the traditional three macronutrients). This is due to mounting evidence suggesting that fiber contributes to our health both directly (e.g., increased satiety, cancer prevention) and indirectly (promoting a healthy microbiome inside our intestinal tract)⁷. For the best health results from fiber, the latest research suggests we aim to eat 30 different plant sources a week⁸.

6. Sleep is as important to our metabolic health—maybe more!—than nutrition and exercise.

We can survive years without exercise and months without food. But even a week without sleep can be fatal. This is because sleep regulates inflammation, mitochondrial function, hormone function, appetite, energy expenditure, and even emotional function.

Insufficient or low-quality sleep affects us much like acute and chronic stressors, activating our fight-or-flight response to promote short-term survival over long-term health⁹. Based on this research, better sleep could be the single most effective change for many people to improve their health and quality of life.

7. If you're confused about nutrition, it is intentional.

Whether you get your nutrition information from the internet, social media, or even scientific journals in 2024, the likelihood that what you're reading has been influenced by the food industry is high. Social media influencers are increasingly paid by the food industry to market misinformation. Most funding for nutritional research also comes from food industry sources, with data overwhelming showing that this biases the results. And undisclosed conflicts of interest among nutrition researchers and government nutrition guideline panel members are disturbingly common.

Sadly, much of the food industry-funded influence is designed specifically to promote confusion among researchers and consumers—much like the tobacco company-funded studies clouded cigarette-cancer research in the 20th century—that enables them to continue marketing unequivocally unhealthy but highly profitable foods¹⁰.

8. Food deserts and food swamps: The importance of the food environment for our health.

Food deserts refer to places with limited access to fresh and nutritious food, whereas food swamps refer to areas with a high density of ultra-processed food sources (e.g., fast food restaurants) per person. Although they may sound different, many people in the U.S. live in both a food desert and a food swamp. And more and more evidence shows that each is toxic to our metabolic health¹¹. Improving the health of the U.S. food environment is arguably the most important—but also most challenging—change needed to reduce our growing burden of chronic health conditions.

9. The metabolic hydra: How Alzheimer's disease, cancers, depression, diabetes, heart disease, liver disease, low testosterone, obesity, and PCOS may all be the same disease.

The final but possibly most important finding emerging from the weight loss and metabolic health field in 2024 is recognizing the interconnection between diseases we traditionally considered distinct. This insight has once again been fueled by the new, injectable weight-loss medicines.

In recent studies using these medicines, researchers have observed large improvements in heart disease, sleep apnea, liver and kidney diseases, blood sugar, blood pressure, and cholesterol—in addition to their already established efficacy for treating obesity and diabetes¹². The healthcare implications of this new understanding of metabolic diseases are enormous. Rather than the current healthcare model using dozens of specialty clinics and thousands of specialized medicines and procedures to treat health conditions, perhaps we just need a handful of clinics armed with more effective tools for treating metabolic diseases.