Staying consistent with a diet

Three randomized trials put popular or contrasting diets side by side and measured who kept following them. In the first, 160 adults were assigned to Atkins, Zone, Weight Watchers, or Ornish, and mean weight loss at one year ran from 2.1 kg to 3.3 kg across the four groups (Dansinger et al., JAMA, January 2005). Amount of weight loss was associated with self-reported dietary adherence level (r = 0.60) and was not associated with diet type (r = 0.07), and only 50% to 65% of each group completed the year (Dansinger 2005). The authors' conclusion names the real problem: overall dietary adherence rates were low, although increased adherence was associated with greater weight loss for each diet group.

The second trial assigned 811 adults to four diets with different shares of fat, protein, and carbohydrate (Sacks et al., NEJM, February 2009). At 6 months every group had lost an average of 6 kg, about 7% of initial weight, and they began to regain after 12 months. By two years weight loss was similar across all four diets, and attendance at group sessions was strongly associated with weight loss, at 0.2 kg per session attended (Sacks 2009). The conclusion was that reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize.

The third put 609 adults on a healthy low-fat or a healthy low-carbohydrate diet for 12 months (Gardner et al., DIETFITS, JAMA, February 2018). Weight change was -5.3 kg on low-fat and -6.0 kg on low-carbohydrate, a difference of 0.7 kg that was not significant, and neither genotype pattern nor baseline insulin secretion predicted which diet worked better for whom (DIETFITS 2018).

The obesity guideline from the American Heart Association, the American College of Cardiology, and The Obesity Society reads the same literature and says a variety of dietary approaches can produce weight loss in overweight and obese adults (AHA/ACC/TOS, Circulation, November 2013).

One trial linked the first weeks to later results. Among 2,290 Look AHEAD participants in an intensive lifestyle program, weight loss at months 1 and 2 was associated with yearly weight loss through year 8 (Unick et al., Obesity, July 2015). Participants who lost more than 4% in month 1 had 2.79 times the odds of achieving at least 5% weight loss at year 4, compared with those who lost under 2%, and differences in adherence between the groups were observed as early as month 2 (Unick 2015).

That is an association inside one trial of adults with type 2 diabetes, so it describes a group and predicts nothing about you. The authors' own next step points at the person who starts slowly: future studies should examine whether alternative treatment strategies can be employed to improve outcomes among those with low initial weight loss (Unick 2015).

The 1998 federal obesity guideline calls recording what you eat a key step in behavior therapy. Patients should be taught to record the amount and types of food they eat, and extending records to time, place, and feelings related to eating will help to bring previously unrecognized behavior to light (NHLBI Clinical Guidelines, September 1998). CDC's version for the public is shorter: include everything you consume for a few days in a food and beverage diary, which will help you see what you eat and drink and consider how to make small changes (CDC, Steps for Losing Weight, last reviewed January 17, 2025). NIDDK adds one instruction, which is to record not only what you did, but how you felt while doing it (NIDDK, Changing Your Habits for Better Health, last reviewed November 2020).

A systematic review of 22 studies found a significant association between self-monitoring and weight loss consistently, and graded the evidence weak because of methodologic limitations, mainly homogeneous samples and reliance on self-report, with samples that were predominantly white and women in all but two studies (Burke et al., J Am Diet Assoc, January 2011).

Frequency on its own was not enough in one trial of 220 women followed for a year after treatment. More food records helped only when they were coupled with weekly consistency of more than 3 days a week, and how detailed the records were made no difference to weight change (Peterson et al., Obesity, September 2014).

For weight loss maintenance, the AHA/ACC/TOS guideline says to monitor body weight regularly, meaning weekly or more frequently (AHA/ACC/TOS, November 2013). A review of 17 longitudinal studies found regular self-weighing was associated with more weight loss and was not associated with adverse psychological outcomes such as depression or anxiety, while noting that the frequency studied varied across studies (Zheng et al., Obesity, February 2015).

In the National Weight Control Registry, self-monitoring weight is one of the habits members report (Wing and Phelan, Am J Clin Nutr, July 2005), and over 10 years, decreases in frequency of self-weighing were associated with greater weight regain (Thomas et al., Am J Prev Med, January 2014).

The registry is a group of adults who at entry had lost at least 30 lbs and kept it off for at least a year, and its data is observational and self-reported (Thomas 2014). Members report high levels of physical activity, a low-calorie, low-fat diet, eating breakfast regularly, self-monitoring weight, and maintaining a consistent eating pattern across weekdays and weekends (Wing and Phelan 2005).

One registry paper tested the weekday and weekend question directly. Among 1,429 members followed for a year, those who reported a consistent diet across the week were 1.5 times more likely to maintain their weight within 5 pounds than those who dieted more strictly on weekdays, and the same pattern held for consistency across holidays and vacations (Gorin et al., Int J Obes, February 2004).

The guideline's instruction on how often someone should be in touch is specific. It says to prescribe high-intensity comprehensive weight loss interventions of at least 14 sessions in 6 months, then long-term participation of at least 1 year in a maintenance program, with regular contact monthly or more frequently with a trained interventionist (AHA/ACC/TOS, November 2013). In the Diabetes Prevention Program, researchers met with participants individually at least 16 times in the first 24 weeks, and then every 2 months with at least 1 phone call between visits (NIDDK, DPP, last reviewed August 2021).

The public pages put it in plainer terms. Identify family members or friends who will support your weight loss efforts (CDC, January 17, 2025). Ask a friend or family member for help when you need it, and always try to plan ahead (NIDDK, November 2020). Share your weight loss plan with someone you trust (NHS, Tips to help you lose weight, last reviewed 17 March 2023).

Every public source here expects a setback and says what to do next. Occasional setbacks happen, this is expected, and when they happen you should get back on track as quickly as possible (CDC, January 17, 2025). A setback does not mean you have failed, all of us experience setbacks, and the instruction is to regroup and focus on meeting your goals again as soon as you can (NIDDK, November 2020). NIDDK also asks you to overcome roadblocks by planning ahead for setbacks (NIDDK, November 2020).

The 1998 guideline goes further and describes the thought that turns one slip into a lost day. Patients should be encouraged to reevaluate setbacks and ask "What did I learn from this attempt?" instead of punishing themselves (NHLBI, September 1998). Its example is the thought "I blew my diet this morning by eating that doughnut; I may as well eat what I like for the rest of the day," which it asks to replace with "Well, I ate the doughnut this morning, but I can still eat in a healthy manner at lunch and dinner" (NHLBI, September 1998).

The goal itself can set up the lapse. Setting unrealistic goals, such as losing 20 pounds in 2 weeks, can leave you feeling defeated and frustrated (CDC, January 17, 2025). NIDDK's example of a workable goal is "I'm going to walk for 10 minutes, three times a week," and it suggests a nonfood reward after reaching a goal or milestone (NIDDK, November 2020).

I keep the food log from what you text me or a photo of the plate, every day, so the diary the CDC and NHLBI describe exists without you writing it. The guideline and the DPP both built frequent contact into their programs (AHA/ACC/TOS, 2013; NIDDK DPP, August 2021), and mine is a text every morning and a question about the day at night. Weigh in when you weigh in and text me the number, and I keep the trend. On Sunday I read the week back to you, weekdays and weekend side by side, because consistency across the week is the pattern the registry found (Gorin 2004).

After a bad day I ask what happened and what the next meal is. That is the doughnut rule from the 1998 guideline, and it is the part I hold with you.

I never pick your diet, I never set your calorie level, and I never diagnose anything. If you have a plan from a dietitian or your doctor, we follow that plan.

No clinician reviewed this page. It restates the trials, reviews, and CDC, NIDDK, NHLBI, NHS, and AHA/ACC/TOS documents linked below, and those are the documents to trust over anything here.