The reset diet is a short-term eating plan designed to jumpstart weight loss by temporarily replacing most meals with smoothies, soups, or other simplified foods before gradually reintroducing solid meals. The most well-known version is the Body Reset Diet, a 15-day program created by celebrity trainer Harley Pasternak, though several variations exist under the “reset” label. The core idea across all of them: strip your diet down to basics for a set period, then rebuild eating habits from scratch.
How the Body Reset Diet Works
The Body Reset Diet lasts 15 days and is divided into three five-day phases. Each phase increases the amount of solid food you eat while decreasing your reliance on smoothies. The daily calorie count stays low throughout, with smoothies running roughly 270 to 325 calories each.
Phase 1 (Days 1 through 5): You drink three smoothies per day plus two high-fiber snacks. No solid meals. This is the most restrictive stage, designed to cut calories sharply and, according to the plan, kickstart your metabolism.
Phase 2 (Days 6 through 10): Two smoothies per day, with one solid meal added back. That meal is meant to be a single-dish option like a salad, stir-fry, or soup.
Phase 3 (Days 11 through 15): One smoothie per day and two solid meals. By the end of this phase, you’re eating close to a normal pattern again, just with lighter, lower-calorie choices.
The program also encourages light physical activity, primarily walking, throughout the 15 days. The exercise component is intentionally gentle since calorie intake is significantly reduced.
What You Can Eat
Smoothies in the Body Reset Diet typically combine fruit, vegetables, protein (like Greek yogurt or protein powder), and a fiber source such as flaxseed or chia seeds. The high-fiber snacks in Phase 1 might include things like celery with almond butter or a small portion of nuts.
When solid meals return in Phases 2 and 3, the emphasis is on lean proteins like chicken, turkey, fish, eggs, or tofu. Healthy fats come from avocado, olive oil, nuts, and seeds. Carbohydrates lean toward vegetables and low-glycemic fruits: berries, green apples, grapefruit. Whole grains like quinoa or brown rice are sometimes included, particularly if you’re exercising regularly. The overall food list looks similar to many clean-eating programs, just delivered in smoothie form for most of the plan.
Other Diets That Use the “Reset” Label
The Body Reset Diet isn’t the only program using this term. Several other plans market themselves as dietary resets, each with a different approach. One popular alternative is a five-day bone broth cleanse, which centers meals around collagen-rich broths paired with simple whole foods. Other versions run anywhere from 7 to 21 days and focus on eliminating processed foods, sugar, alcohol, and dairy before slowly reintroducing them to identify sensitivities.
What these programs share is a philosophy of temporary restriction followed by a structured return to regular eating. The specifics vary widely, so if someone recommends a “reset diet,” it’s worth asking which one they mean.
Does It Actually Reset Your Metabolism?
The central marketing claim of most reset diets is that they retrain your body to burn calories more efficiently. The science behind this is thin. No strong clinical evidence shows that a 15-day smoothie plan permanently changes your metabolic rate. What does happen is straightforward: when you eat significantly fewer calories, you lose weight. Some of that loss, especially in the first few days, is water weight from reduced carbohydrate intake, not fat loss.
There is some evidence that dietary changes can shift the balance of bacteria in your gut, which plays a role in inflammation, insulin sensitivity, and how your body processes food. Reducing populations of certain inflammatory bacteria while increasing beneficial ones could have metabolic benefits over time. But these shifts require sustained dietary changes, not just a two-week program.
Side Effects to Expect
Switching abruptly from a typical diet to one that’s almost entirely liquid and high in fiber can cause digestive discomfort. Gas, bloating, and constipation are common, especially if you weren’t eating much fiber before. Increasing water intake during the transition helps, but some adjustment period is unavoidable as your gut bacteria adapt to the new food sources.
Headaches and brain fog are another frequent complaint. Your brain runs on glucose, and when calorie intake drops sharply or carbohydrate intake falls below what your body is used to, you may not have enough readily available fuel. This can leave you feeling mentally sluggish, particularly during Phase 1. People who normally consume a lot of sugar may also experience something similar to withdrawal. Sugar activates some of the same reward pathways in the brain as other habit-forming substances, so cutting it out abruptly can trigger cravings, irritability, and headaches.
Fatigue is also common. At roughly 800 to 1,000 calories per day during Phase 1, most people are eating well below their energy needs. This is why the plan recommends only light exercise rather than intense workouts.
Who It Works For and Who Should Be Cautious
The Body Reset Diet can produce noticeable weight loss in 15 days simply because of the calorie deficit. For someone looking for a structured, short-term plan to break out of poor eating habits, the gradual reintroduction of solid food can serve as a useful framework for building better meals going forward.
The bigger question is what happens on Day 16. Very low-calorie diets often lead to rebound eating once the restriction ends, and the weight lost during the program can return quickly if old habits resume. The plan works best as a launching point rather than a standalone solution. People with a history of disordered eating, blood sugar management issues, or those who are pregnant or nursing should be particularly careful with any program that drops calories this low for days at a time.
The lasting value of a reset diet depends less on the 15 days themselves and more on whether the experience changes how you eat afterward. The smoothie phases are temporary by design. The habits you build around whole foods, fiber, lean protein, and portion awareness are what determine whether the results stick.