The Best Diet: Most people know that being overweight and obese are health concerns that must be addressed. We are a nation where nearly 50% of the US population is obese (BMI greater than 30).1 Weight is a modifiable risk factor for chronic diseases like type 2 diabetes and heart disease.2
Given these statistics, it’s no wonder people are searching for a magic weight-loss bullet. Billions of dollars are spent by consumers each year on weight loss plans or supplements for a quick fix.3 Meanwhile, the economic effect of weight-related diseases and loss of productivity is estimated to be more than 1.7 trillion dollars.4
Something needs to change. Based on research, it appears that most people can lose weight. Keeping the weight off to support long-term health benefits remains the problem.
So is there one best diet? The short answer is no. But with diet variation, we can achieve known benefits of well-studied diet interventions (specifically keto, low-carb, and fasting). These interventions support long-term health changes.
Weight loss maintenance is a problem.
Long-term weight loss requires significant changes in lifestyle, behavior, and diet. People have difficulty maintaining weight loss for various reasons– from hormonal to psychological factors.5
Research tells us that more than half of those who lose weight will regain it within two years, and by five years, 80% will gain it again.6 The body will start seeing weight loss patterns as a stressful event after yo-yo dieting. Therefore, it will work hard to hold onto weight each time weight loss is attempted.
It can be challenging to maintain a diet pattern if it feels too restrictive. As the body adapts to the changes, weight loss plateaus can occur due to hormonal adaptations. Many standard diets focus on cutting down on calories. With this approach, the body will eventually respond by decreasing the metabolic rate and increasing hunger cues. These hormonal adaptations make you more hungry, making losing weight difficult.7 Once this occurs, weight loss plateaus, we lose health benefits (and sometimes end up feeling worse), and motivation decreases, making it challenging to adhere to the diet.
Is there a diet that addresses long-term maintenance?
Most people following a new diet or meal plan will result in weight loss and health benefits (some bigger and some smaller). Diets will differ in macronutrient content (i.e., protein, fat, carbs) or even caloric amounts. However, they usually share one thing in common: an increase in nutrient-dense foods and a decrease in processed foods.
What happens after 6-12 months of the diet matters. And research tends to be lacking here. Most of the studies do not examine long-term effects that occur over time as the body adapts.
If you look at studies on some of the most popular diets right now, you will likely find robust, peer-reviewed, published research on their efficacy.
A recent paper comparing intermittent fasting, paleo, and Mediterranean diets found minimal differences in health outcomes between the diets after 12 months. However, the authors also noted there were significant dropout rates.8 Even in a well-designed study with additional support, participants had difficulty sticking to one diet.
If you dig a little deeper into the research, you will likely be able to find positive outcomes noted for many different diets.
In reality, there is no one perfect diet for each of us that leads to long-term changes. We all have different circumstances, genetics, gender, ages, and health concerns that affect how our body responds to a diet. For example, a study conducted by German scientists found that in 800 different glycemic measurements taken after meals, people responded significantly differently to eating the exact same thing.9
When a nutrition study comes out, the resulting headlines will be translated to the public as a whole, even if it is based on a small group of people. But we can’t always say that every person will respond the same way. And when we focus on specific nutrients, science tries to pinpoint the reason, but it’s not always possible. We can make general statements about healthy foods, but beyond that, it is highly individualized. For example, in low-carb studies (which clearly have a lot of benefits backed up in the research), when a person cuts down on carb intake, they will usually increase protein and fat in the diet to make up for it. Are the positive changes just from reducing the carbs, or are they also from a reduction in calories, an increase in protein, or fat – or all above? 10
It’s no wonder people are confused and overwhelmed!
Consider the quality of food and the timing of intake.
Working with a practitioner to individualize your diet is ideal – but it may not be just about the diet itself. Instead, we can consider the food quality and the timing of intake. This is the approach I teach in my diet variation principles using fasting and keto with cycles of increased carbs. We can use our innate biological adaptations and current lifestyles to support realistic long-term changes.
Deficit diets are not the answer.
It is clear that cutting back on portions does not work long-term for the average person11, so caloric deficit diets are not necessarily the answer. At the same time, while I fully support successful diets like keto or paleo, they can also lead to long-term unhealthy adaptations for some people if too restrictive.
As you just read, even in research studies, it can be challenging to keep people motivated to stay on a diet long-term. Another study looking at the difference between a low-carb diet and a low-fat diet found that participants in the low-carb diet were supposed to eat less than 20 grams of carbohydrates but ended up eating closer to 100 grams daily.12 If they could cycle with higher carb days, they might have been able to continue with the intervention as it was designed.
A well-planned cycle of diet variation can help avoid problems with plateauing and adaptations and psychologically help with feelings of deprivation. Studies usually examine a single diet change – but with diet variation, we can utilize multiple well-studied eating patterns to achieve positive health changes for weight loss and beyond.
- “Adult Obesity Facts.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 27 Feb. 2020, www.cdc.gov/obesity/data/adult.html.
- “Heart Disease and Stroke.” Heart Disease and Stroke | Healthy People 2020, www.healthypeople.gov/2020/topics-objectives/topic/heart-disease-and-stroke.
- Greenway, F L. “Physiological adaptations to weight loss and factors favoring weight regain.” International journal of obesity (2005) vol. 39,8 (2015): 1188-96. doi:10.1038/ijo.2015.59
- Hall, Kevin D, and Scott Kahan. “Maintenance of Lost Weight and Long-Term Management of Obesity.” The Medical clinics of North America vol. 102,1 (2018): 183-197. doi:10.1016/j.mcna.2017.08.012
- Hall, K.D. (2018), Metabolic Adaptations to Weight Loss. Obesity, 26: 790-791. doi:10.1002/oby.22189
- Michelle R Jospe, Melyssa Roy, Rachel C Brown, Jillian J Haszard, Kim Meredith-Jones, Louise J Fangupo, Hamish Osborne, Elizabeth A Fleming, Rachael W Taylor, Intermittent fasting, Paleolithic, or Mediterranean diets in the real world: exploratory secondary analyses of a weight-loss trial that included choice of diet and exercise, The American Journal of Clinical Nutrition, Volume 111, Issue 3, March 2020, Pages 503–514, https://doi.org/10.1093/ajcn/nqz330
- Sample, Ian. “Bespoke Diets Based on Gut Microbes Could Help Beat Disease and Obesity.” The Guardian, Guardian News and Media, 10 June 2015, www.theguardian.com/science/2015/jun/10/personalised-diets-diabetes-obesity-heart-disease-microbes-microbiomes.
- Weaver, Connie M, and Joshua W Miller. “Challenges in conducting clinical nutrition research.” Nutrition reviews vol. 75,7 (2017): 491-499. doi:10.1093/nutrit/nux026
- Harry R Kissileff, John C Thornton, Migdalia I Torres, Katherine Pavlovich, Laurel S Mayer, Vamsi Kalari, Rudolph L Leibel, Michael Rosenbaum, Leptin reverses declines in satiation in weight-reduced obese humans, The American Journal of Clinical Nutrition, Volume 95, Issue 2, February 2012, Pages 309–317, https://doi.org/10.3945/ajcn.111.012385
- Gardner, Christopher D, et al. “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 vol. 319,7 (2018): 667-679. doi:10.1001/jama.2018.0245