Modest goals cut diabetes risk 58% in a landmark trial, and yours can be just as small

Key takeaways

• In the Diabetes Prevention Program, a lifestyle plan aiming for 7% weight loss and 150 minutes of weekly activity cut the risk of type 2 diabetes by 58%¹.
• A 2017 review of 141 papers found that setting a goal improves behavior by a small amount, and hard goals worked better than easy ones³.
• The SMART checklist traces to a 1981 management article, and a 2023 review found it has little scientific support for promoting physical activity⁵⁶.
• In a Swedish study of 1,066 New Year’s resolutions, 58.9% of people with goals to start something succeeded, compared with 47.1% of people with goals to stop or avoid something⁶.
• The CDC says losing 5% to 10% of your weight, or 10 to 20 pounds for a 200-pound person, can improve your health⁷.

In 1996, a federal study began enrolling 3,234 Americans at high risk for type 2 diabetes. One group was asked to do something that sounds almost too modest: lose 7% of their body weight and move for 150 minutes a week¹.

For a 200-pound person, 7% is 14 pounds, nowhere near the dramatic before-and-after goals you see in ads.

Yet over about three years, people in the lifestyle group cut their chance of getting diabetes by 58% compared with a placebo group. Among people 60 and older, the drop was 71%¹. The study, called the Diabetes Prevention Program, ran at 27 centers and was sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)¹.

The lesson reaches beyond diabetes: a goal doesn’t have to be big to matter, but it has to be the right size, the right kind and something you can keep doing.

We walk through what goal research shows, where popular advice runs ahead of the evidence, and a template for writing goals that survive a bad week.

Setting a goal helps, but less than you might think

In 2017, psychologists Tracy Epton, Sinead Currie and Christopher Armitage pooled randomized trials that tested goal setting by itself³. In a randomized trial, people are assigned by chance to one group or another. The review covered 141 papers and 16,523 people³.

Setting a goal did help, though not by much. Researchers measure the size of an effect with a number called d, where zero means no difference, and the average here was 0.34, which the authors called small³.

Three things made goals work better. Hard goals beat easy ones, with a d of 0.45 versus 0.25, and goals made public or set by a group also had bigger effects³.

Some popular beliefs didn’t show up in the data. It didn’t matter whether people chose their own goal or someone else set it³. Goals about actions, such as “walk daily,” didn’t clearly beat goals about results, such as “lose 10 pounds”³.

There’s a catch: two-thirds of the studies recruited university students, and about half the goals involved mental tasks rather than health habits³. Health studies were a small slice, just 21 of the effects measured, though their average was a bit larger, at 0.44³.

Hard goals work, until the goal turns into a fantasy

Edwin Locke and Gary Latham spent about 35 years studying goals, mostly at work and in labs. In 2002 they summed up the research in the journal American Psychologist⁴. Their core finding: specific, hard goals beat vague advice to “do your best”⁴.

Performance rose with goal difficulty in a fairly straight line, leveling off only when people hit the limits of their ability or lost commitment to a very hard goal⁴.

That last part is where many health goals break. Commitment is strongest when a goal feels important and you believe you can reach it, the authors wrote⁴. A goal you secretly doubt doesn’t pull you forward.

New skills need a different kind of goal, because when a task was new or complex, a tough results goal could make people anxious and scattered⁴. A learning goal, such as mastering a set of strategies, worked better⁴. Near-term goals stacked under a long-term one also raised confidence and results⁴.

Picture someone who has never cooked dinner from scratch. “Lose 30 pounds by June” is a results goal that depends on a skill they don’t have yet. “Learn five simple dinners this month” is a learning goal that builds toward it.

This is a rule of thumb, our suggestion rather than a tested cutoff: choose a goal that stretches you but that you’d rate about 7 or 8 out of 10 for confidence. Below that, shrink the goal; at a 10, you can probably aim higher.

SMART goals came from management, not health trials

You’ve probably heard that goals should be SMART: specific, measurable, achievable, realistic and time-bound. The acronym is usually credited to a 1981 article by G.T. Doran in the business journal Management Review⁶. Even the words behind the letters vary from one source to another⁶.

In 2023, a team of 10 researchers led by Christian Swann reviewed how SMART is used to promote physical activity⁵. They concluded that SMART isn’t grounded in scientific theory and doesn’t line up with the research evidence⁵. They also found that it ignores what kind of goal is being set, is applied inconsistently and may sometimes cause harm⁵.

A Swedish experiment adds a twist, in which researchers randomly assigned 1,066 people with New Year’s resolutions to three levels of support⁶. One group got extra coaching on goal setting, including SMART goals and interim goals.

That group did not do better than the group with the least support: 52.5% versus 55.9% succeeded⁶. The winner, at 62.3%, was the middle group, which got a support person and monthly check-ins without the extra coaching, a result the researchers said surprised them⁶.

None of this makes “specific” or “measurable” bad ideas. Specific, hard goals have decades of research behind them⁴, so the lesson is that SMART is a handy checklist, not a tested treatment.

Aim toward something, not only away from it

The same Swedish study sorted resolutions by how they were worded⁶. Approach goals aim toward a new action, such as starting to eat breakfast. Avoidance goals aim to stop or avoid something, such as cutting out sweets.

After a year, 58.9% of people with approach goals said they had succeeded, compared with 47.1% of people with avoidance goals⁶. About 65% of the resolutions were approach goals⁶.

This comparison wasn’t randomized. People picked their own wording, success was self-reported, and the coached group was also told to use approach wording but didn’t do better⁶. Three of the authors earn royalties from a book partly based on the study, which they disclosed⁶. Treat the finding as promising, not proven.

Still, flipping a goal costs nothing. “Quit soda” becomes “drink sparkling water with lunch.” “Stop staying up late” becomes “lights out by 10:30.” You keep the same aim and give yourself something to do.

Pair a result you want with actions you control

Many people set only an outcome goal: a number on the scale, a blood pressure reading, a lab result. Outcome goals give direction, but you can’t control them day to day, and they can shift for reasons that have nothing to do with effort.

A process goal names an action you can check off today: walk after dinner, cook at home four nights, be in bed by 10:30.

The research doesn’t crown a winner, since Epton’s review found no clear difference between action goals and outcome goals³. But strong real-world programs use both, as the Diabetes Prevention Program did when it paired a weight target with a weekly activity target¹.

NIDDK’s guide to preventing type 2 diabetes works the same way, suggesting a weight goal and then smaller steps toward it: begin with walks of 5 to 10 minutes, layer in a new healthy habit or two each week, keep a log of food and activity, and think ahead about what could get in the way⁸.

Early progress seems to matter. In a group program adapted from the Diabetes Prevention Program, described by NIDDK in 2022, how people did by week 5 predicted their results at month 4¹⁰. People who lost less than 2.5% in the first month got extra support, and they still lost weight and lowered their blood sugar¹⁰.

For weight, 5% to 10% is the target with evidence

If weight is part of your plan, “realistic” has a number: the CDC says losing 5% to 10% of your body weight can improve your health. That’s 10 to 20 pounds for a 200-pound person⁷. For people with diabetes, it can make blood sugar easier to manage and may reduce the need for medicine⁷.

NIDDK suggests reaching that range within about six months, at roughly 1 to 2 pounds a week⁸. The original trial set its target at 7%, according to NIDDK¹. The CDC’s page on its national program describes what the original participants lost: 5% to 7%, or 10 to 14 pounds for a 200-pound person².

Even less may help, according to a 2024 review by researchers at University College London that looked at 70 studies of weight loss under 5%⁹. Most of the health measures involved metabolism or the heart. In 60% of the studies, people improved on at least some of them, while 37% found no change or mixed results⁹.

That review had limits: most studies lasted a year or less, and about 4 in 5 had a moderate or high risk of bias⁹.

Weight goals aren’t right for everyone: if you have a history of an eating disorder, are pregnant, or take medicine that lowers blood sugar or blood pressure, set any weight or diet goal with your clinician first.

A goal-writing template, with three worked examples

Use these eight parts to write one goal. Fill them in on paper, keep it where you’ll see it, and work on one goal at a time.

1. Why it matters: one line about what you care about.
2. Direction: the result you’re aiming for, sized realistically.
3. Weekly action: what you’ll do, how often, where and when, worded as something to start.
4. Confidence check: rate 0 to 10 how sure you are. Aim for about 7 or 8.
5. Learning goal: if the action needs a new skill, name the skill to build first⁴.
6. Early marker: what progress at week 4 or 5 should look like¹⁰.
7. Who knows: one person or group you’ll tell³.
8. Review date: when you’ll check in and resize the goal.

The three people below are hypothetical examples, not real cases.

Part	Example A: more movement	Example B: prediabetes	Example C: better sleep
Why it matters	Energy for weekend hikes with family	Avoid the diabetes medicines her mother needed	Fewer afternoon energy crashes
Direction	Work up to 150 minutes of brisk walking a week by month 3, the federal target for adults12	Lose 7%, or 14 pounds from 200, over about six months18	Feel rested on most workdays, rated 7 out of 10 or better
Weekly action	Walk 15 minutes after lunch on workdays, starting Monday	Cook dinner at home four nights; walk 30 minutes five days	Lights out by 10:30 on weeknights; phone charges in the kitchen
Confidence	8	7	7
Learning goal	None needed	Learn five simple, vegetable-heavy dinners this month	Try two wind-down routines; keep the one that helps
Early marker	Four of five walks done most weeks	Down about 5 pounds, or 2.5%, by week 510	Four of five weeknights on schedule
Who knows	A coworker who walks too	Her spouse, plus a CDC-recognized program2	Roommate
Review date	First Sunday of each month	Monthly weigh-in	Every two weeks

Notice what the examples share: each has one outcome, a few actions you can check off, and a first-month marker that tells you early whether to adjust.

What the evidence shows

Idea	What studies found	Evidence level
Setting a goal at all	Small average benefit across 141 papers3	Strong evidence of a small effect
Harder goals over easy ones	Bigger effects; gains level off at the limits of ability34	Strong evidence
Telling others or setting goals as a group	Larger effects in pooled trials3	Promising but early
Learning goals for new or complex skills	Beat tough results goals on complex tasks, mostly in workplace and lab studies4	Promising but early
Approach wording over avoidance wording	58.9% vs 47.1% success; not randomized6	Promising but early
Action goals over outcome goals	No clear difference in pooled trials3	Not enough evidence
The SMART formula itself	Little theory or trial support; coaching that included it didn’t beat minimal support in one trial56	Not enough evidence
Losing 5% to 10% of body weight	Improves health; a 7% target plus activity cut diabetes risk 58%17	Strong evidence
Losing less than 5%	60% of 70 studies found some improvement; many at risk of bias9	Promising but early

Small, steady aims fit natural-health values

Many health traditions prize moderation and patience, such as eating a little less, walking every day and resting at night, and they rarely promise a new body in 30 days.

The research rewards the same instincts. The Diabetes Prevention Program’s goals were modest and built on food and movement, and the lifestyle program beat a drug, metformin, which cut risk by 31%¹. Researchers who study habits advise starting with small, manageable changes, because simple actions become automatic faster and early failure can be discouraging¹¹.

There’s also a self-protective reason to aim realistically. Products that promise dramatic results are selling a dream goal. A modest goal you set yourself is much harder to sell back to you.

Questions readers ask

The bottom line

Goals help, but by a modest amount, and their shape matters more than their size. Aim for a stretch you believe in, name actions you can do this week, word them as something to start, and tell someone.

If weight is part of the plan, 5% to 10% is a target with real evidence behind it, and even less can help. Treat SMART as a checklist, not science, and review your goal often enough to resize it before it breaks.

Related reading

• Old habits run on cues rather than willpower, and you can rewire them
• Your heart counts the weekly total while your habits count the repeats
• Name your values before a health decision, because a pros-and-cons list isn’t enough
• Feeling better after trying something isn’t a test, but you can run one
• Tracking your progress works best when you write it down and tell someone

Sources

1. National Institute of Diabetes and Digestive and Kidney Diseases. “Diabetes Prevention Program (DPP).” NIH, reviewed August 2021. niddk.nih.gov
2. Centers for Disease Control and Prevention. “What Is the National DPP?” CDC, 2024. cdc.gov
3. Epton T, Currie S, Armitage CJ. “Unique effects of setting goals on behavior change: Systematic review and meta-analysis.” Journal of Consulting and Clinical Psychology, 2017. dspace.stir.ac.uk
4. Locke EA, Latham GP. “Building a practically useful theory of goal setting and task motivation: A 35-year odyssey.” American Psychologist, 2002. goal-lab.psych.umn.edu
5. Swann C, Jackman PC, Lawrence A, et al. “The (over)use of SMART goals for physical activity promotion: A narrative review and critique.” Health Psychology Review, 2023. researchportal.scu.edu.au
6. Oscarsson M, Carlbring P, Andersson G, Rozental A. “A large-scale experiment on New Year’s resolutions: Approach-oriented goals are more successful than avoidance-oriented goals.” PLoS ONE, 2020. pmc.ncbi.nlm.nih.gov
7. Centers for Disease Control and Prevention. “Healthy Weight.” CDC Diabetes, updated May 15, 2024. cdc.gov
8. National Institute of Diabetes and Digestive and Kidney Diseases. “Your Game Plan to Prevent Type 2 Diabetes.” NIH, reviewed February 2017. niddk.nih.gov
9. Dhar D, Packer J, Michalopoulou S, et al. “Assessing the evidence for health benefits of low-level weight loss: a systematic review.” International Journal of Obesity, 2025 (online 2024). nature.com
10. National Institute of Diabetes and Digestive and Kidney Diseases. “Providing additional lifestyle intervention based on initial progress can improve weight loss to prevent diabetes.” NIH, 2022. niddk.nih.gov
11. Gardner B, Lally P, Wardle J. “Making health habitual: the psychology of ‘habit-formation’ and general practice.” British Journal of General Practice, 2012. pmc.ncbi.nlm.nih.gov
12. Centers for Disease Control and Prevention. “Adult Activity: An Overview.” CDC, December 20, 2023. cdc.gov