Here’s why you may be having difficulty losing weight

Losing weight is no easy feat for most people. You may feel like you are doing all the right things by eating well or exercising regularly. So, why are your scales not showing you the results that you expect?

The internet is rife with weight loss and nutrition tips, like eating more protein to help you lose weight. But many of these tips aren’t backed up by good quality science.

At ZOE, we run the largest nutrition research program of its kind — with over 10,000 contributors so far — to better understand how our bodies respond to food. 

Together with our world leading academic collaborators, we research the impact of the gut microbiome, exercise, sleep, and stress on metabolic health. 

We know that weight loss journeys can be really hard. That’s why we’ve put together six reasons why you might not be seeing the weight loss that you expect.  

Your weight can have a big impact on your health. Obesity increases the risk of health conditions like heart disease, type 2 diabetes, and some forms of cancer. 

But not everyone needs to lose weight. If your body mass index (BMI) is in the bottom of the moderate weight range or in the underweight range, you don’t need to lose weight. 

Everyone is different. At ZOE, we know that “one-size-fits-all” advice for weight and health don’t work. Instead, the ZOE program helps you learn to eat the right foods for your unique body, your weight, and your overall health. 

Read on to learn about the six reasons why you may not be losing weight. 

1. You're too focused on calories

It’s true that cutting calories can lead to weight loss. But restricting your food intake is hard to sustain and focuses on the quantity of food, not the quality. Many people who lose weight this way rapidly regain it soon after. 

When you don’t eat enough food, your body goes into survival mode. Research has shown that losing weight fast by restricting calories this way reduces your metabolic rate, which is the speed at which you burn calories. 

A lower metabolic rate means that your body needs fewer calories and you will have to eat less food every day to maintain your weight. 

It can take years for your metabolic rate to recover from crash dieting. 

At ZOE, we don’t believe in counting calories as the best approach for weight loss. We know from our research that the way your body responds to food is unique and we encourage you to eat more of the foods that work for you. 

The ZOE program teaches you which foods work best for your body and how to combine them so that you can make any food work for you. 

Unpublished ZOE research shows that when participants closely followed their personalized gut-healthy nutrition program, around 80% didn’t feel hungry and had more energy. The average weight loss was 9.4 pounds after 3 months.

2. You’re not eating the right foods for your body and your metabolism

Our ground-breaking research has found that no two people respond to food in the same way, even identical twins. Your metabolism is not fully defined by your genes, you can learn to manage and maintain a healthy metabolism through diet and lifestyle changes.

There isn’t one type of weight loss diet that works for everyone. In one of the most detailed clinical trials, researchers found that how much weight the participants lost on different diets varied greatly, and some even put on weight. 

Our PREDICT research program has shown that there are large variations in blood sugar, blood fat, and insulin responses to the same meal between different people. 

This means that an identical meal can cause large blood sugar spikes and dips in one person but not in another. These big spikes and dips can make it more likely you’ll feel hungry again soon after eating and can contribute to poor health in the long run. 

If you eat the right foods for your body, your weight and overall health will benefit. That’s why the ZOE at-home test kit analyzes your unique blood fat and blood sugar responses to identify the best food for your body. 

3. You're not looking after your gut microbiome

Your gut microbiome is the community of trillions of bacteria and other microbes living within your gut. It plays a major role not only in how you digest food, but also in your overall health. Each person’s gut microbiome is unique. 

Having good gut health reduces the risk of many chronic conditions like obesity, type 2 diabetes, heart disease, autoimmune conditions, and possibly cancer. 

Research has found that the gut microbiomes of people with obesity are very different to those of people with a moderate weight. Your gut bugs may be one of the reasons why you are not seeing the weight loss you are expecting. 

ZOE scientists have identified 15 “good” and 15 “bad” gut bugs associated with better and worse indicators of health. They also identified what types of food these microbes are linked to.

The ZOE program identifies your personal “gut booster” foods to support your gut microbiome. It also suggests what “gut suppressor” foods to avoid that may not be great for your gut health.

4. You're not getting enough sleep

Poor sleep has been linked with serious health conditions like type 2 diabetes and heart disease. And there’s growing evidence that people who don’t get enough sleep have a higher risk of obesity or weight gain. 

When you don’t sleep enough, you are also more likely to reach for sweeter foods.

ZOE scientists recently showed that going to bed earlier is better for your blood sugar response the next morning. Having a later bedtime or going to bed later than usual, on the other hand, led to worse blood sugar responses.

Bringing your bedtime forward can help you avoid big blood sugar spikes and dips that can make you feel hungry again soon after eating. These big spikes and dips also make you more likely to opt for ultra-processed foods, which increases your risk of overweight and obesity

ZOE's PREDICT program also found that eating highly processed foods is linked with more of the “bad” gut bugs.

5. You're losing fat but gaining muscle

If you are eating well and going to the gym but aren’t seeing a shift in the scale, it may be because you are gaining muscle, which is more dense than fat. This means you could weigh the same, even if your body composition has changed.

Strength training can help you build muscle, but it can also increase your metabolic rate, which means your body will burn extra calories throughout the day. 

Your lack of weight loss in terms of pounds measured on a scale may be a perfectly healthy result of exercising more. But don’t rely on exercise alone to lose weight.

6. You're not measuring your success in other ways

There are many ways to measure your progress while you are on your weight loss journey that don’t involve stepping on a scale.

Try these and find what works best for you:

  • Are your clothes fitting more loosely?

  • Do you feel and look different?

  • Have your energy levels changed?

  • Has your digestion improved?

  • Are you sleeping better?

  • How is your mood?


If you are eating a healthy diet or being more active but are not losing weight, you are not alone. Weight loss is challenging for many people and there is no one-size-fits-all solution to weight. 

Focus on eating the right foods for your body and your unique gut microbiome rather than counting and restricting calories.

Prioritize your sleep to help keep your blood sugar levels in check and avoid large spikes and dips that can make you feel hungry again soon after eating. 

If you are exercising, remember that you may be putting on muscle while losing fat. This could be the reason why your weight isn’t changing. 

Find the best way that works for you to check on your progress. This might involve noticing changes in how you feel and look, or seeing if your mood and digestion have improved. 

At ZOE, we know that eating the right foods for your body is good for your health and for your weight. Take our free quiz to find out how ZOE can help you make food work for you. 

The ZOE at-home test kit  analyzes your blood sugar and blood fat responses, as well as your gut microbiome, to identify the best foods and food combinations for your metabolic health and your gut bugs.


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Effect of low-fat vs low-carbohydrate diet on 12-month weight loss in overweight adults and the association with genotype pattern or insulin secretion — The DIETFITS randomized clinical trial. JAMA. (2018).

Inadequate Sleep as a Contributor to Obesity and Type 2 Diabetes. Canadian Journal of Diabetes. (2013). 

Role of the gut microbiome in chronic diseases: a narrative review. European Journal of Clinical Nutrition. (2021).

Specific metabolic rates of major organs and tissues across adulthood: evaluation by mechanistic model of resting energy expenditure. The American journal of clinical nutrition. (2010).  

The effect of exercise interventions on resting metabolic rate: A systematic review and meta-analysis. Journal of sports sciences. (2020). 

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